arXiv subjects

Pramod Ghising

Publications and source records attributed to Pramod Ghising.

3 recordsLinked to original sources

arXiv2023

Ferromagnetism and Metal-Insulator transition in F-doped LaMnO3

We present our studies on polycrystalline samples of fluorine doped LaMnO3 (LaMnO3-yFy). LaMnO2.5F0.5 exhibits remarkable magnetic and electrical properties. It shows ferromagnetic and metallic behavior with a high Curie temperature of ~ 239 K and a high magnetoresistance of -64. This drastic change in magnetic properties in comparison to pure LaMnO3 is ascribed to the presence of mixed-valence Mn ions driven by the F-doping at the O-sites, which enables double exchange (DE) in LMOF. Furthermore, the resistivity data exhibits two resistivity peaks at 239 K and 213 K, respectively. Our results point towards the possibility of multiple double exchange hopping paths of two distinct resistances existing simultaneously in the sample below 213 K.

cond-mat.str-el↗

arXiv2019

Electric field control of photoinduced effect in La$_{0.7}$Sr$_{0.3}$MnO$_3$/LaTiO$_3$/SrTiO$_3$ heterostructure

In this work we have studied the effect of light and electric field on the electrical properties of La0.7Sr0.3MnO3 (LSMO) film at 300 K. Taking advantage of it's charge, spin, orbital and lattice degrees of freedom, we have successfully shown that light and electric field together can be used to tune the resistance states of the manganite system. Using applied gate voltage (Vg) and light we were able to obtain a change in resistance of about +/-7.5%. Furthermore, incorporating an ultra thin interfacial LaTiO3 (LTO) layer provides valuable insight on the origin of the photoinduced effect. The observed photoinduced effect is attributed to photoexcited down spin eg electrons, interfacial charge injection and manipulation of orbital occupancy depending on the gate voltage and wavelength of light.

cond-mat.str-el↗

arXiv2018

Kondo effect with tunable spin orbit interaction in LaTiO3/CeTiO3/SrTiO3 heterostructure

We have fabricated epitaxial films of CeTiO3 (CTO) on (001)oriented SrTiO3(STO) substrates, which exhibit highly insulating and diamagnetic properties. X-ray photoelectron spectroscopy (XPS) was to establish the 3+ valence state of the Ve and Ti ions. Furthermore, we also fabricated delta (CTO) doped LatiO3 (LTO)-STO thin films which exhibit variety of interesting properties including Kondo effect and spin orbit interaction (SOI) at low temperatures. SOI shows a non-monotonic behaviour as the thickness of the CTO layer is increased and is reflected in the value of the characteristic SOI field (B_SO) obtained from weak antilocalization fitting. The maximum value of B_SO is 1.00 T for delta layer thickness of 6 u.c. This non-monotonic behaviour of SOI is attributed to the strong screening of the confining potential at the interface. The thicker CTO film in addition to the increased dielectric constant of the STO substrate at low temperature leads to strong screening as a result of which the electrons confined at the interface are spread deeper into the STO bulk where it starts to populate the Ti d_xz_yz subbands; consequently the Fermi level crosses over from the d_xy to the d_xz_yz subbands. At the crossover region of d_xy - d_xz_yz where there is orbital mixing, SOI goes through a maximum.

cond-mat.str-el↗