Related papers: Zener double exchange from local valence fluctuati…
We apply the self-interaction corrected local spin density %(SIC-LSD) approximation to study the electronic structure and magnetic properties of the spinel ferrites MnFe$_{2}$O$_{4}$, Fe$_{3}$O$_{4}$, CoFe$_{2}$O$_{4}$, and…
We have studied structural, magnetic and transport properties as a function of temperature and magnetic field in the electron doped manganite YxCa1-xMnO3, for 0<x<0.25. We found that in the paramagnetic regime, the magnetic susceptibility,…
Single crystalline (Bi,Ca)MnO3 (74< %Ca <82) were studied with neutron scattering, electron diffraction and bulk magnetic measurement. We discovered dynamic ferromagnetic spin correlations at high temperatures, which are replaced by…
Monoclinic Y$_{0.7}$Er$_{0.3}$Fe$_2$D$_{4.2}$ compound exhibits unusual magnetic properties with different field induced magnetic transitions. The deuteride is ferrimagnetic at low temperature and the Er and Fe sublattices present magnetic…
The isothermal magnetic entropy change has been obtained for the bilayer system that consists of $S_u$ and $S_l$ valued spins in each layer. The relation between the IMEC and the spin value as well as the value of exchange interaction…
Spin excitation spectrum of the double-exchange model is studied in the presence of randomness. Spin wave approximation in the ground state shows that the randomness significantly modifies the spectrum from the cosine-like one in the pure…
We study a classical double exchange magnet with direct antiferromagnetic superexchange coupling, J, between the localized spins. It is shown that the de-stabilization of the ferromagnetic ground state with increasing J leads to phase…
This study investigates Mn-Zn ferrites (nominal composition \ce{Mn_{0.5}Zn_{0.5}Fe2O4}, MZF) substituted with tetravalent (\ce{Si^{4+}}), trivalent (\ce{Co^{3+}}), and divalent (\ce{Ca^{2+}}, \ce{Mg^{2+}}, \ce{Sn^{2+}}) ions. We…
Vertical ferroelectricity where a net dipole moment appears as a result of in-plane ionic displacements has gained enormous attention following its discovery in transition metal dichalcogenides. Based on first-principles calculations, we…
Motivated by recent discovery of colossal magnetoresistance in La$_(1-x)$Ca$x$MnO$_3$ and other manganites, we have studied the double exchange model. We argue that the forced alignment of conduction-electron spin with the core spins that…
The discovery of high-temperature superconductivity in bilayer nickelate La$_{3}$Ni$_{2}$O$_{7}$ necessitates a minimal theoretical model that unifies the superconducting phase with the spin-density-wave (SDW) phase without external…
Using the degenerate double exchange Hamiltonian with on-site Coulomb interactions we show that there is an instability towards the displacement of the manganese ion in La_{1-x}Ca_{x}MnO_{3}. The result is a dipole moment due to the charge…
A microscopic model of indirect exchange interaction between transition metal impurities in dilute magnetic semiconductors (DMS) is proposed. The hybridization of the impurity d-electrons with the heavy hole band states is largely…
Powder neutron diffraction experiments have been employed to establish the effects of site-selective magnetic dilution in the Sm2MnMnMn4-x Tix O12 A-site columnar ordered quadruple perovskite manganites (x = 1, x = 2 and x = 3). We show…
It has been long suspected that spin fluctuations in the weak itinerant ferromagnet ZrZn2 may lead to a triplet superconductivity in this material. Here we point out another possibility, a spatially inhomogeneous singlet superconducting…
The electronic structure of perovskite manganese oxides is investigated in terms of a Kondo lattice model with ferromagnetic Hund coupling and antiferromagnetic exchange between $t_{2g}$-spins using a finite temperature diagonalization…
A lightly doped perovskite mangantite La_{0.88}Sr_{0.12}MnO_3 exhibits a phase transition at T_{OO}=145 K from a ferromagnetic metal (T_C=172 K) to a novel ferromagnetic insulator.We identify that the key parameter in the transition is the…
A mechanism for charge-ordered ferromagnetic phase in manganites is proposed. The mechanism is based on the double exchange in the presence of diagonal disorder. It is modeled by a combination of the Ising double-exchange and the…
We present results of our broadband ellipsometry measurements of the optical response of ferromagnetic La$_{0.7}$Sr$_{0.3}$CoO$_3$. Our data show that the ferromagnetic transition is accompanied by a transfer of optical spectral weight from…
We report a neutron powder diffraction study of $R$Mn$_7$O$_{12}$ quadruple perovskite manganites with $R$ = La, Ce, Nd, Sm, and Eu. We show that in all measured compounds concomitant magnetic ordering of the $A$ and $B$ manganese…