相关论文: Disorder-Induced First Order Transition and Curie …
Effects of disorder on the two competing phases, i.e., the ferromagnetic metal and the commensurate charge/lattice ordered insulator, are studied by Monte Carlo simulation. The disorder suppresses the charge/lattice ordering more strongly…
In the present work we analyze the influence of the charge-ordering on the magnetocaloric effect of Pr$_{1-x}$Ca$_x$MnO$_3$ manganites. The results for the samples with $x<$0.30 present the usual ferromagnetic behavior, peaking at the Curie…
The unusual magneto-transport properties of manganites are widely believed to be caused by mixed-phase tendencies and concomitant percolative processes. However, dramatic deviations from "standard" percolation have been unveiled…
We investigate the effect of chemical disorder on the magnetic exchange couplings and the Curie temperature ($T_{\text{c}}$) in L1$_0$-ordered FeNi using first-principles-based calculations. We use supercells to model chemical disorder, to…
We consider consequences of local disorder in systems experiencing first order phase transitions. Such systems can be of rather different nature. For example, manganates showing gigantic magnetoelectric effect, doped antiferroelectrics or…
The physics of manganites appears to be dominated by phase competition among ferromagnetic metallic and charge-ordered antiferromagnetic insulating states. Previous investigations (Burgy {\it et al.}, Phys. Rev. Lett. {\bf 87}, 277202…
The influence of quenched disorder on the competition between ordered states separated by a first-order transition is investigated. A phase diagram with features resembling quantum-critical behavior is observed, even using classical models.…
We theoretically investigate impurity correlation and magnetic clustering effects on the long-range ferromagnetic ordering in diluted magnetic semiconductors, such as $\textrm{Ga}_{1-x}\textrm{Mn}_{x}\textrm{As}$, using analytical arguments…
We develop a variational mean-field theory of the ferromagnetic transition in compounds like Lanthanum-Manganite within the framework of the Double-Exchange Model supplemented by modest disorder. We obtain analytical expressions for the…
We theoretically explore the mechanism of the colossal magnetoresistance in manganese oxides by explicitly taking into account the phase competition between the double-exchange ferromagnetism and the charge-ordered insulator. We find that…
We quantitatively discuss the influence of quenched disorder on the ferromagnetic quantum phase transition in metals, using a theory that describes the coupling of the magnetization to gapless fermionic excitations. In clean systems, the…
Influence of disorder on the ferromagnetic phase transition in diluted (III,Mn)V semiconductors is investigated analytically. The regime of small disorder is addressed, and the enhancement of the critical temperature by disorder is found…
In low-dimensional magnets, thermal agitation and spatial disorders generate strong spin fluctuations that suppress the long-range magnetic ordering. We develop an analytical equation for the equilibrium magnetization of two-dimensional…
In the manganites $RE_{1-x}AE_{x}$MnO$_{3}$ ($RE$ and $AE$ being rare-earth and alkaline-earth elements, respectively) the random distribution of $RE^{3+}$ and $AE^{2+}$ induces random, but correlated, shifts of site energies of charge…
The influence of configurational disorder on the magnetic properties of diluted Heisenberg spin systems is studied with regard to the ferromagnetic stability of diluted magnetic semiconductors. The equation of motion of the magnon Green's…
We give an overview on several recent topics of colossal magnetoresistive manganites in both experiments and theories, focusing on the effect of quenched disorder. The disorder is intrinsically involved since the compounds are solid…
Based on the two-variable polynomial model of magnetization, magnetic entropy change of bilayered manganites with $327$-structure and its scaling behaviour with respect to applied magnetic fields are investigated. It's found that the Curie…
Ultrasonic attenuation and phase velocity measurements have been carried out in the ferromagnetic perovskites La_{2/3}Ca_{1/3}MnO_3 and La_{2/3}Sr_{1/3}MnO_3. Data show that the transition at the Curie temperature, T_C, changes from first-…
Large scale Monte Carlo simulation results for the two-orbital model for manganites, including Jahn-Teller lattice distortions, are here presented. At hole density x=1/4 and in the vicinity of the region of competition between the…
The effects of sintering temperature (Ts) and chemical substitution on the structural and magnetic properties of manganite compounds La1-xSrxMn1-yFeyO3 (0.025 <= x <= 0.7; y= 0.01,0.15) are explored in a search to optimize their…