arXiv subjects

A. M. Strydom

Publications and source records attributed to A. M. Strydom.

At least 37 records · Page 2Linked to original sources

arXiv2017

Pr-magnetism in the quasi-skutterudite compound PrFe$_2$Al$_8$

The intermetallic compound \PFA\ that possesses a three-dimensional network structure of Al polyhedra centered at the transition metal element Fe and the rare earth Pr is investigated through neutron powder diffraction and inelastic neutron scattering in order to elucidate the magnetic ground state of Pr and Fe and the crystal field effects of Pr. Our neutron diffraction study confirms long-range magnetic order of Pr below $T_N $ = 4.5~K in this compound. Subsequent magnetic structure estimation reveals a magnetic propagation vector $k$ = ($\frac{1}{2}$~0~$\frac{1}{2}$) with a magnetic moment value of 2.5~$μ_\mathrm{B}$/Pr along the orthorhombic $c$-axis and evidence the lack of ordering in the Fe sublattice. The inelastic neutron scattering study reveals one crystalline electric field excitation near 19~meV at 5~K in \PFA. The energy-integrated intensity of the 19~meV excitation as a function of |$Q$| $(A^{-1})$ follows the square of the magnetic form factor of Pr$^{3+}$ thereby confirming that the inelastic excitation belongs to the Pr sublattice. The second sum rule applied to the dynamic structure factor indicates only 1.6(2)~$μ_\mathrm{B}$ evolving at the 19~meV peak compared to the 3.58~$μ_\mathrm{B}$ for free Pr$^{3+}$, indicating that the crystal field ground state is magnetic and the missing moment is associated with the resolution limited quasi-elastic line. The magnetic order occurring in Pr in \PFA\ is counter-intuitive to the symmetry-allowed crystal field level scheme, hence, is suggestive of exchange-mediated mechanisms of ordering stemming from the magnetic ground state of the crystal field levels.

cond-mat.str-el↗

arXiv2017

Nodal superconducting gap structure in the quasi-one-dimensional Cs$_2$Cr$_3$As$_3$ investigated using $μ$SR measurements

The superconducting ground state of the newly discovered superconductor Cs$_2$Cr$_3$As$_3$ with a quasi-one-dimensional crystal structure ($T_{\bf c}\sim$ 2.1(1) K) has been investigated using magnetization and muon-spin relaxation or rotation ($μ$SR), both zero-field (ZF) and transverse-field (TF), measurements. Our ZF $μ$SR measurements reveal the presence of spin fluctuations below 4 K and the ZF relaxation rate ($λ$) shows enhancement below $T_{\bf c}\sim$ 2.1 K, which might indicate that the superconducting state is unconventional. This observation suggests that the electrons are paired via unconventional channels such as spin fluctuations, as proposed on the basis of theoretical models. Our analysis of the TF $μ$SR results shows that the temperature dependence of the superfluid density is fitted better with a nodal gap structure than an isotropic s-wave model for the superconducting gap. The observation of a nodal gap in Cs$_2$Cr$_3$As$_3$ is consistent with that observed in the isostructural K$_2$Cr$_3$As$_3$ compound through TF $μ$SR measurements. Furthermore, from our TF $μ$SR study we have estimated the magnetic penetration depth $λ_{\mathrm{L}}$$(0)$ = 954 nm, superconducting carrier density $n_s = 4.98 \times 10^{26}~ $m$^{-3}$, and carrier's effective-mass enhancement $m^*$ = 1.61m$_{e}$.

cond-mat.supr-con↗

arXiv2017

Missing magnetism in Sr$_{4}$Ru$_{3}$O$_{10}$: Indication for Antisymmetric Exchange Interaction

We report a detailed study of the magnetization modulus as a function of temperature and applied magnetic field under varying angle in Sr$_{4}$Ru$_{3}$O$_{10}$ close to the metamagnetic transition at $H_{c}\backsimeq 2.5\,$T for $H \perp c$. We confirm that the double-feature at $H_{c}$ is robust without further splitting for temperatures below 1.8 K down to 0.48 K. The metamagnetism in Sr$_{4}$Ru$_{3}$O$_{10}$ is accompanied by a reduction of the magnetic moment in the plane of rotation and large field-hysteretic behavior. The double anomaly shifts to higher fields by rotating the field from $H\,\perp \,c$ to $H\,\parallel\,c$. We compare our experimental findings with numerical simulations based on spin reorientation models caused by intrinsic magnetocrystalline anisotropy and Zeeman effect. Crystal anisotropy is able to explain a metamagnetic transition in the ferromagnetic ordered system Sr$_{4}$Ru$_{3}$O$_{10}$, but a Dzyaloshinskii-Moriya term is crucial to account for a reduction of the magnetic moment as discovered in the experiments.

cond-mat.str-el↗

arXiv2016

Magnetic, specific heat and electrical transport properties of Frank-Kasper cage compounds RTM$_2$Al$_{20}$ [R = Eu,Gd and La ; TM = V,Ti]

Single crystals of Frank-Kasper compounds RTM$_2$Al$_{20}$ (R = Eu, Gd and La; TM = V and Ti) were grown by self-flux method and their physical properties were investigated through magnetization ($M$), magnetic susceptibility ($χ$), specific heat ($C_P$) and electrical resistivity ($ρ$) measurements. Powder x-ray diffraction studies and structural analysis showed that these compounds crystallize in the cubic crystal structure with the space group $Fd\overline{3}m$. The magnetic susceptibility for the compounds EuTi$_2$Al$_{20}$ and GdTi$_2$Al$_{20}$ showed a sudden jump below the N{é}el temperature $T_N$ indicative of plausible double magnetic transition. Specific heat ($C_P$) and electrical resistivity ($ρ$) measurements also confirm the first-order magnetic transition (FOMT) and possible double magnetic transitions. Temperature variation of heat capacity showed a sharp phase transition and huge $C_P$ value for the (Eu/Gd)Ti$_2$Al$_{20}$ compounds Full width at half-maximum (FWHM) $<$ 0.2 K) which is reminiscent of a first-order phase transition and a unique attribute among RTM$_2$Al$_{20}$ compounds. We observed clear anomaly between heating and cooling cycle in temperature-time relaxation curve for the compounds GdTi$_2$Al$_{20}$ (2.38 $K$) and EuTi$_2$Al$_{20}$ (3.2 $K$) which is indicating a thermal arrest due to the latent heat. The temperature variation of $S_{mag}$ for GdTi$_2$Al$_{20}$ saturates to a value $0.95R\ln8$ while the other magnetic systems exhibited still lower entropy saturation values in the high temperature limit. Resistivity measurements showed that all the samples behave as normal Fermi liquid type compounds and $ρ(T)$ due to electron-phonon scattering follows Bloch-Gr$\ddot{\textrm u}$neisen-Mott relation in the paramagnetic region.

cond-mat.mtrl-sci↗

arXiv2016

Temperature dependence of exchange biased multiferroic $ \mathbf{BiFeO_3} $/$ \mathbf{Ni_{81}Fe_{19}} $ polycrystalline bilayer

The temperature dependence of exchange bias properties are studied in polycrystalline $ \mathrm{BiFeO_3} / \mathrm{Ni_{81}Fe_{19}} $ bilayers, for different $ \mathrm{BiFeO_3} $ thicknesses. Using a field cooling protocol, a non-monotonic behavior of the exchange bias field is shown in the exchange-biased bilayers. Another thermal protocol, the Soeya protocol, related to the $ \mathrm{BiFeO_3} $ thermal activation energies was carried out and reveals a two-step evolution of the exchange bias field. The results of these two different protocols are similar to the ones obtained for measurements previously reported on epitaxial $ \mathrm{BiFeO_3} $, indicating a driving mechanism independent of the long-range crystalline arrangement (i.e., epitaxial or polycrystalline). An intrinsic property of $ \mathrm{BiFeO_3} $ is proposed as being the driving mechanism for the thermal dependent magnetization reversal: the canting of the $ \mathrm{BiFeO_3} $ spins leading to a biquadratic contribution to the exchange coupling. The temperature dependence of the magnetization reversal angular behavior agrees with the presence of such a biquadratic contribution for exchange biased bilayers studied here.

cond-mat.mtrl-sci↗

arXiv2016

Magneto-transport properties of CeRu$_2$Al$_{10}$: Similarities to URu$_2$Si$_2$

We report on magneto-transport properties of the Kondo semiconducting compound CeRu$_2$Al$_{10}$, focusing on its exotic phase below $T_0$ = 27 K. In this phase, an excess thermal conductivity $κ$ emerges and is gradually suppressed by magnetic field, strikingly resembling those observed in the hidden-order phase of URu$_2$Si$_2$. Our analysis indicates that low-energy magnetic excitation is the most likely origin, as was also proposed for URu$_2$Si$_2$ recently, despite the largely reduced magnetic moments. Likewise, other transport properties such as resistivity, thermopower and Nernst effect exhibit distinct features characterizing the very different charge dynamics above and below $T_0$, sharing similarities to URu$_2$Si$_2$, too. Given the exotic nature of the ordered phases in both compounds, whether a unified interpretation to all these observations exists appears to be extremely interesting.

cond-mat.str-el↗

arXiv2016

Crystal field states of Kondo lattice heavy fermions CeRuSn3 and CeRhSn3

Inelastic neutron scattering experiments have been carried out to determine the crystal field states of the Kondo lattice heavy fermions CeRuSn3 and CeRhSn3. Both the compounds crystallize in LaRuSn3-type cubic structure (space group Pm-3n) in which the Ce atoms occupy two distinct crystallographic sites with cubic (m-3) and tetragonal (-4m.2) point symmetries. The INS data of CeRuSn3 reveal the presence of a broad excitation centered around 6-8 meV which is accounted by a model based on crystal electric field (CEF) excitations. On the other hand, the INS data of isostructural CeRhSn3 reveal three CEF excitations around 7.0, 12.2 and 37.2 meV. The neutron intensity sum rule indicates that the Ce ions at both cubic and tetragonal Ce sites are in Ce3+ state in both CeRuSn3 and CeRhSn3. The CEF level schemes for both the compounds are deduced. We estimate the Kondo temperature T_K = 3.1(2) K for CeRuSn3 from neutron quasielastic linewidth in excellent agreement with that determined from the scaling of magnetoresistance which gives T_K = 3.2(1) K. For CeRhSn3 the neutron quasielastic linewidth gives T_K = 4.6 K. For both CeRuSn3 and CeRhSn3, the ground state of Ce3+ turns out to be a quartet for the cubic site and a doublet for the tetragonal site.

cond-mat.str-el↗

arXiv2016

Converse effect of pressure on quadrupolar and magnetic transition in Ce$_{3}$Pd$_{20}$Si$_{6}$

The heavy fermion compound Ce$_{3}$Pd$_{20}$Si$_{6}$ displays unconventional quantum criticality as the lower of two consecutive phase transitions is fully suppressed by magnetic field. Here we report on the effects of pressure as additional tuning parameter. Specific heat and electrical resistivity measurements reveal a converse effect of pressure on the two transitions, leading to the merging of both transitions at 6.2 kbar. The field-induced quantum criticality is robust under pressure tuning. We rationalize our findings within an extended version of the global phase diagram for antiferromagnetic heavy fermion quantum criticality.

cond-mat.str-el↗

arXiv2016

Field-insensitive heavy fermion features and phase transition in the caged-structure quasi-skutterudite Sm$_3$Ru$_4$Ge$_{13}$

The robust field-insensitive heavy fermion features in Sm$_3$Ru$_4$Ge$_{13}$ and the magnetic phase transition at $T_N \approx$ 5~K are studied using magnetization $M(T)$, specific heat $C_p(T)$, resistivity $ρ(T)$ and thermal conductivity $κ_T(T)$. The average crystal structure of Sm$_3$Ru$_4$Ge$_{13}$ conforms to the cubic space group $Pm\bar{3}n$ however, signatures of subtle structural distortions are obtained from the x ray data. The magnetic susceptibility, $χ(T)$, follows a modified Curie-Weiss law indicating the presence of crystal fields of Sm$^{3+}$ and the significance of van Vleck terms. No sign of ferromagnetism is observed in $M(H)$ of Sm$_3$Ru$_4$Ge$_{13}$ which yields only 0.025~$μ_\mathrm{B}$/f.u.-Sm at 2~K, 7~T. The Sommerfeld coefficient, $γ\approx$ 220~mJ/mol-Sm K$^2$, estimated from the analysis of low temperature specific heat suggests the formation of heavy quasi particles at low temperature. Though a ln$T$ dependence of $ρ(T)$ is observed till 60~K, the resistivity behavior is accounted for by assuming a two-band model for activated behavior of charge carriers. The field scans of resistivity, $ρ(H)$, below $T_N$ display significant nonlinearity while those above the $T_N$ are more metal-like. Low values of thermal conductivity, $κ_T(T)$, are observed in Sm$_3$Ru$_4$Ge$_{13}$ however, displaying an anomaly at $T_N$ which signifies magnetoelastic coupling. A fairly high value of Seebeck coefficient, $S \approx$ 40~$μ$V/K is observed at 300~K. We identify Sm$_3$Ru$_4$Ge$_{13}$ as a low charge carrier density system with unusual field-insensitive heavy fermion features very similar to the filled skutterudites.

cond-mat.str-el↗

arXiv2016

Magnetic structures and magnetic phase transitions in the Mn-doped orthoferrite TbFeO$_3$ studied by neutron powder diffraction

The magnetic structures and the magnetic phase transitions in the Mn-doped orthoferrite TbFeO$_3$ studied using neutron powder diffraction are reported. Magnetic phase transitions are identified at $T^\mathrm{Fe/Mn}_N \approx$ 295~K where a paramagnetic-to-antiferromagnetic transition occurs in the Fe/Mn sublattice, $T^\mathrm{Fe/Mn}_{SR} \approx$ 26~K where a spin-reorientation transition occurs in the Fe/Mn sublattice and $T^\mathrm{R}_N \approx$ 2~K where Tb-ordering starts to manifest. At 295~K, the magnetic structure of the Fe/Mn sublattice in TbFe$_{0.5}$Mn$_{0.5}$O$_3$ belongs to the irreducible representation $Γ_4$ ($G_xA_yF_z$ or $Pb'n'm$). A mixed-domain structure of ($Γ_1 + Γ_4$) is found at 250~K which remains stable down to the spin re-orientation transition at $T^\mathrm{Fe/Mn}_{SR}\approx$ 26~K. Below 26~K and above 250~K, the majority phase ($> 80\%$) is that of $Γ_4$. Below 10~K the high-temperature phase $Γ_4$ remains stable till 2~K. At 2~K, Tb develops a magnetic moment value of 0.6(2)~$μ_\mathrm{B}/$f.u. and orders long-range in $F_z$ compatible with the $Γ_4$ representation. Our study confirms the magnetic phase transitions reported already in a single crystal of TbFe$_{0.5}$Mn$_{0.5}$O$_3$ and, in addition, reveals the presence of mixed magnetic domains. The ratio of these magnetic domains as a function of temperature is estimated from Rietveld refinement of neutron diffraction data. Indications of short-range magnetic correlations are present in the low-$Q$ region of the neutron diffraction patterns at $T < T^\mathrm{Fe/Mn}_{SR}$. These results should motivate further experimental work devoted to measure electric polarization and magnetocapacitance of TbFe$_{0.5}$Mn$_{0.5}$O$_3$.

cond-mat.str-el↗

arXiv2016

Incommensurate spin-density-wave antiferromagnetism in CeRu$_2$Al$_2$B

The newly discovered Ising-type ferromagnet CeRu$_2$Al$_2$B exhibits an additional phase transition at $T_\textrm{N}$ = 14.2 K before entering the ferromagnetic ground state at $T_\textrm{C}$ = 12.8 K. We clarify the nature of this transition through high resolution neutron diffraction measurements. The data reveal the presence of a longitudinal incommensurate spin-density wave (SDW) in the temperature range of $T_\textrm{C}<T<T_\textrm{N}$. The propagation vector ${\bf q} \sim (0,0,0.148)$ is nearly temperature independent in this region and discontinuously locks into ${\bf q} = 0$ at $T_\textrm{C}$. Mean-field calculations of an effective Ising model indicate that the modulated SDW phase is stabilized by a strong competition between ferromagnetic and antiferromagnetic exchange interactions. This makes CeRu$_2$Al$_2$B a particularly attractive model system to study the global phase diagram of ferromagnetic heavy-fermion metals under influence of magnetic frustration.

cond-mat.str-el↗

arXiv2015

Destruction of Kondo effect in cubic heavy fermion compound Ce3Pd20Si6

How ground states of quantum matter transform between one another reveals deep insights into the mechanisms stabilizing them. Correspondingly, quantum phase transitions are explored in numerous materials classes, with heavy fermion compounds being among the most prominent ones. Recent studies in an anisotropic heavy fermion compound have shown that different types of transitions are induced by variations of chemical or external pressure [1-3], raising the question of the extent to which heavy fermion quantum criticality is universal. To make progress, it is essential to broaden both the materials basis and the microscopic parameter variety. Here, we identify a cubic heavy fermion material as exhibiting a field-induced quantum phase transition, and show how the material can be used to explore one extreme of the dimensionality axis. The transition between two different ordered phases is accompanied by an abrupt change of Fermi surface, reminiscent of what happens across the field-induced antiferromagnetic to paramagnetic transition in the anisotropic YbRh2Si2. This finding leads to a materials-based global phase diagram -- a precondition for a unified theoretical description.

cond-mat.str-el↗

arXiv2015

Searching for triplet superconductivity in the Quasi-One-Dimensional K2Cr3As3

The superconducting state of the newly discovered superconductor K$_2$Cr$_3$As$_3$ with a quasi-one-dimensional crystal structure ($T_{\bf c}\sim$ 6 K) has been investigated by using magnetization and muon-spin relaxation or rotation ($μ$SR) measurements. Our analysis of the temperature dependence of the superfluid density obtained from the transverse field (TF) $μ$SR measurements fit very well to an isotropic $s$-wave character for the superconducting gap. Furthermore a similarly good fit can also be obtained using a $d$-wave model with line nodes. Our zero-field $μ$SR measurements do reveal very weak evidence of the spontaneous appearance of an internal magnetic field near the transition temperature, which might indicate that the superconducting state is not conventional. This observation suggests that the electrons are paired via unconventional channels such as spin fluctuations, as proposed on the basis of theoretical models of K$_2$Cr$_3$As$_3$. Furthermore, from our TF $μ$SR study the magnetic penetration depth $λ_L$, superconducting carrier density $n_s$, and effective-mass enhancement $m^*$ have been estimated to be $λ_L(0)$ = 454(4) nm, $n_s$ = 2.4$\times$10$^{27}$ carriers/m$^3$, and $m^*$ = 1.75 $m_e$, respectively.

cond-mat.supr-con↗

arXiv2015

Large Seebeck Effect by Charge-Mobility Engineering

The Seebeck effect describes the generation of an electric potential in a conducting solid exposed to a temperature gradient. Besides fundamental relevance in solid state physics, it serves as a key quantity to determine the performance of functional thermoelectric materials. In most cases, it is dominated by an energy-dependent electronic density of states at the Fermi level, in line with the prevalent efforts toward superior thermoelectrics through the engineering of electronic structure. Here, we demonstrate an alternative source for the Seebeck effect based on charge-carrier relaxation: A charge mobility that changes rapidly with temperature can result in a sizeable addition to the Seebeck coefficient. This new Seebeck source is demonstrated explicitly for Ni-doped CoSb3, where a dramatic mobility change occurs due to the crossover between two different charge-relaxation regimes. Our findings unveil the origin of pronounced features in the Seebeck coefficient of many other elusive materials characterized by a significant mobility mismatch. As the physical origin for the latter can vary greatly, our proposal provides a unifying framework for the understanding of a large panoply of thermoelectric phenomena. When utilized appropriately, this effect can also provide a novel route to the design of improved thermoelectric materials for applications in solid-state cooling or power generation.

cond-mat.mtrl-sci↗

arXiv2015

Contrasting chemical pressure effect on the moment direction in the Kondo semiconductor CeT$_2$Al$_{10}$ (T = Ru,Os)

The opening of a spin gap in the orthorhombic compounds CeT$_2$Al$_{10}$ (T = Ru and Os) is followed by antiferromagnetic ordering at $T_N$ = 27 K and 28.5 K, respectively, with a small ordered moment (0.29$-$0.34$μ_B$) along the $c-$axis, which is not an easy axis of the crystal field (CEF). In order to investigate how the moment direction and the spin gap energy change with 10\% La doping in Ce$_{1-x}$La$_x$T$_2$Al$_{10}$ (T = Ru and Os) and also to understand the microscopic nature of the magnetic ground state, we here report on magnetic, transport, and thermal properties, neutron diffraction (ND) and inelastic neutron scattering (INS) investigations on these compounds. Our INS study reveals the persistence of spin gaps of 7 meV and 10 meV in the 10\% La-doped T = Ru and Os compounds, respectively. More interestingly our ND study shows a very small ordered moment of 0.18 $μ_B$ along the $b-$axis (moment direction changed compared with the undoped compound), in Ce$_{0.9}$La$_{0.1}$Ru$_2$Al$_{10}$, however a moment of 0.23 $μ_B$ still along the $c-$axis in Ce$_{0.9}$La$_{0.1}$Os$_2$Al$_{10}$. This contrasting behavior can be explained by a different degree of hybridization in CeRu$_2$Al$_{10}$ and CeOs$_2$Al$_{10}$, being stronger in the latter than in the former. Muon spin rotation ($μ$SR) studies on Ce$_{1-x}$La$_x$Ru$_2$Al$_{10}$ ($x$ = 0, 0.3, 0.5 and 0.7), reveal the presence of coherent frequency oscillations indicating a long$-$range magnetically ordered ground state for $x$ = 0 to 0.5, but an almost temperature independent Kubo$-$Toyabe response between 45 mK and 4 K for $x$ = 0.7. We will compare the results of the present investigations with those reported on the electron and hole$-$doping in CeT$_2$Al$_{10}$.

cond-mat.str-el↗

arXiv2015

Broken time-reversal symmetry probed by muon spin relaxation in the caged type superconductor Lu$_5$Rh$_6$Sn$_{18}$

The superconducting state of the caged type compound Lu$_5$Rh$_6$Sn$_{18}$ has been investigated by using magnetization, heat capacity, and muon-spin relaxation or rotation ($μ$SR) measurements and the results interpreted on the basis of the group theoretical classifications of the possible pairing symmetries and a simple model of the resulting quasiparticle spectra. Our zero-field $μ$SR measurements clearly reveal the spontaneous appearance of an internal magnetic field below the transition temperature, which indicates that the superconducting state in this material is characterized by the broken time-reversal symmetry. Further the analysis of temperature dependence of the magnetic penetration depth measured using the transverse field $μ$SR measurements suggest an isotropic $s$-wave character for the superconducting gap. This is in agreement with the heat capacity behavior and we show that it can be interpreted in terms of a non unitary triplet state with point nodes and an open Fermi surface.

cond-mat.supr-con↗

arXiv2014

Momentum-space structure of quasielastic spin fluctuations in Ce3Pd20Si6

Among heavy-fermion metals, Ce$_3$Pd$_{20}$Si$_6$ is one of the heaviest-electron systems known to date. Here we used high-resolution neutron spectroscopy to observe low-energy magnetic scattering from a single crystal of this compound in the paramagnetic state. We investigated its temperature dependence and distribution in momentum space, which was not accessible in earlier measurements on polycrystalline samples. At low temperatures, a quasielastic magnetic response with a half-width Γ=0.1 meV persists with varying intensity all over the Brillouin zone. It forms a broad hump centered at the (111) scattering vector, surrounded by minima of intensity at (002), (220) and equivalent wave vectors. The momentum-space structure distinguishes this signal from a simple crystal-field excitation at 0.31 meV, suggested previously, and rather lets us ascribe it to short-range dynamical correlations between the neighboring Ce ions, mediated by the itinerant heavy f-electrons via the RKKY mechanism. With increasing temperature, the energy width of the signal follows the conventional T$\scriptstyle^{1/2}$ law, Γ(T) = Γ$_0$ + A*T$\scriptstyle^{1/2}$. The momentum-space symmetry of the quasielastic response suggests that it stems from the simple-cubic Ce sublattice occupying the 8c Wyckoff site, whereas the crystallographically inequivalent 4a site remains magnetically silent in this material.

cond-mat.str-el↗

arXiv2014

Anomalous change of the magnetic moment direction by hole doping in CeRu$_2$Al$_{10}$

We present a detailed investigation of the hole (3\% Re) doping effect on the polycrystalline CeRu$_{2}$Al$_{10}$ sample by magnetization, heat capacity, resistivity, muon spin rotation ($μ$SR), and neutron scattering (both elastic and inelastic) measurements. CeRu$_2$Al$_{10}$ is an exceptional cerium compound with an unusually high Neel temperature of 27 K. Here we study the stability of the unusual magnetic order by means of controlled doping, and we uncover further surprising attributes of this phase transition. The heat capacity, resistivity and $μ$SR measurements reveal an onset of magnetic ordering below 23 K, while a broad peak at 31 K (i.e. above $T_N$), has been observed in the temperature dependent susceptibility, indicating an opening of a spin gap above $T_N$. Our important finding, from the neutron diffraction, is that the compound orders antiferromagnetically with a propagation vector $\bf k$ = (1 0 0) and the ordered state moment is 0.20(1)$μ_B$ along the $b-$axis. This is in sharp contrast to the undoped compound, which shows AFM ordering at 27 K with the ordered moment of 0.39(3)$μ_B$ along the $c-$axis. Similar to CeRu$_2$Al$_{10}$ our inelastic neutron scattering study on the Re doped shows a sharp spin gap-type excitation near 8 meV at 5 K, but with slightly reduced intensity compared to the undoped compound. Further the excitation broadens and shifts to lower energy ($\le$ 4 meV) near 35 K. These results suggest that the low temperature magnetic properties of the hole doped sample is governed by the competition between the anisotropic hybridization effect and crystal field anisotropy as observed in hole-doped CeOs$_2$Al$_{10}$.

cond-mat.str-el↗