arXiv subjects

I. Kézsmárki

Publications and source records attributed to I. Kézsmárki.

57 records · Page 4Linked to original sources

arXiv2005

Magneto-optics induced by the spin chirality in itinerant ferromagnet Nd$_2$Mo$_2$O$_7$

It is demonstrated both theoretically and experimentally that the spin chirality associated with a noncoplanar spin configuration produces a magneto-optical effect. Numerical study of the two-band Hubbard model on a triangle cluster shows that the optical Hall conductivity $σ_{xy}(ω)$ is proportional to the spin chirality. The detailed comparative experiments on pyrochlore-type molybdates $R_2$Mo$_2$O$_7$ with $R=$Nd (Ising-like moments) and $R=$Gd (Heisenberg-like ones) clearly distinguishes the two mechanisms, i.e., spin chirality and spin-orbit interactions. It is concluded that for $R$=Nd, $σ_{xy}(ω)$ is dominated by the spin chirality for the dc ($ω=0$) and the $d \to d$ incoherent intraband optical transitions between Mo atoms.

cond-mat.str-el↗

arXiv2003

Pressure induced suppression of the singlet insulator phase in BaVS$_3$: infrared optical study

The metal-insulator (MI) transition in BaVS$_3$ has been studied at ambient pressure and under hydrostatic pressure up to $p=26 $kbar in the frequency range of $20-3000 $cm$^{-1}$. The charge gap determined from the optical reflectivity is enhanced, $Δ_{ch}(p)/k_BT_{MI}(p)\sim 12$. This ratio is independent of pressure indicating that the character of the transition does not vary along the $p-T$ phase boundary. Above the critical pressure, $p_{cr}\sim20$ kbar, metallic spectra were recorded in the whole temperature range, as expected from the shape of the phase diagram. Our results exclude the opening of a pseudogap above $T_{MI}$ at any pressure. Below $T_{MI}$ an unusually strong temperature dependence of the charge gap was observed, resulting in a $Δ_{ch}(T)$ deviating strongly from the mean field-like variation of the structural order parameter.

cond-mat.str-el↗

arXiv2000

Giant Magnetoresistance at the Interface of Iron Thin Films

Ag/Fe/Ag and Cr/Fe/Cr trilayers with a single $25 nm$ thick ferromagnetic layer exhibit giant magnetoresistance (GMR) type behavior. The resistance decreases for parallel and transversal magnetic field alignements with a Langevin-type magnetic field dependence up to B=12 T. The phenomenon is explained by a granular interface structure. Results on Fe/Ag multilayers are also interpreted in terms of a granular interface magnetoresistance.

cond-mat.mtrl-sci↗