Related papers: Griffiths phase in solid-solution of ferromagnetic…
The phase diagram of the ferromagnetic Kondo model for manganites is investigated using computational techniques. In clusters of dimensions 1 and 2, Monte Carlo simulations in the limit where the localized spins are classical show a rich…
The effect of disorder on the critical properties of the ferromagnetic phase transition in colossal magnetoresistive manganite La0.67Ca0.33MnO3 has been studied by substituting Ga for Mn. It is found that, upon 10% Ga substitution, the peak…
We investigate the effects of disorder within the T=0 Brinkman-Rice (BR) scenario for the Mott metal-insulator transition (MIT) in two dimensions (2d). For sufficiently weak disorder the transition retains the Mott character, as signaled by…
We have studied the magnetic relaxation properties of the phase-separated manganite compound La0.250Pr0.375Ca0.375MnO3 . A series of polycrystalline samples was prepared with different sintering temperatures, resulting in a continuous…
It was discovered in La1-xSrxMnO3(x~1/8) that a field induced phase transition occurs from a ferromagnetic metal(FM) phase to a ferromagnetic insulator (FI) phase. The magnetization shows a sharp jump at the transition field accompanying…
The geometric phase (GP) for bipartite systems in transverse external magnetic fields is investigated in this paper. Two different situations have been studied. We first consider two non-interacting particles. The results show that because…
We investigate a series of manganese oxides, the La0.225Pr0.4(Ca1-xSrx)0.375MnO3 system. The x = 0 sample is a prototype compound for the study of phase separation in manganites, where ferromagnetic and charge ordered antiferromagnetic…
We study the effects of disorder in the vicinity of the ferromagnetic transition in a diluted magnetic semiconductor in the strongly localized regime. We derive an effective polaron Hamiltonian, which leads to the Griffiths phase above the…
139La NMR spin-lattice relaxation rate 1/T1 and rf enhancement experiments provide evidence that the low temperature regime of the ferromagnetic (FM) phase of La1-xCaxMnO3 segregates into highly-conductive and poorly-conductive FM regions,…
Heavy fermion compounds have long been identified as systems which are extremely sensitive to the presence of impurities and other imperfections. In recent years, both experimental and theoretical work has demonstrated that such disorder…
High resolution neutron diffraction shows that the mesoscopic separation into ferromagnetic (FM) and antiferromagnetic (AFM) phases and the FM transition temperature T_C in the perovskite manganite (La_{1-y}Pr_{y})_{0.7}Ca_{0.3}MnO_3…
The phase diagram of a biased graphene bilayer is computed and the existence of a ferromagnetic phase is discussed both in the critical on-site interaction $U_{c}$ versus doping density and versus temperature. We show that in the…
We report magnetization ($M$) measurements close to the ferromagnetic quantum phase transition of the d-metal alloy Ni$_{1-x}$V$_x$ at a vanadium concentration of $x_c \approx 11.4 %$. In the diluted regime ($x>x_c$), the temperature ($T$)…
The nature of phase separation in $Pr_{0.5}Sr_{0.5}MnO_3$ has been probed by linear as well as nonlinear magnetic susceptibilities and resistivity measurements across the 2nd order paramagnetic to ferromagnetic transition ($T_C$) and 1st…
In order to study the phase diagram from a microscopic viewpoint, we have measured wTF- and ZF-$\mu^+$SR spectra for the Sr$_{1-x}$Ca$_x$Co$_2$P$_2$ powder samples with $x=0$, 0.2, 0.4, 0.5, 0.6, 0.8, and 1. Due to a characteristic time…
We have studied the spin ordering of a dilute classical Heisenberg model with spin concentration $x$, and with ferromagnetic nearest-neighbor interaction $J_1$ and antiferromagnetic next-nearest-neighbor interaction $J_2$. Magnetic phases…
The interest in the study of spin-Peierls phenomenon has increased with the discovery of copper germanium oxide (CuGeO_3) as an example of spin-Peierls systems. The availability of this inorganic compound as large, high quality single…
We study the anisotropic magnetic structures exhibited by electron-doped manganites using a model which incorporates the double-exchange between orbital ly degenerate $e_{g}$ electrons and the super-exchange between $t_{2g}$ electrons with…
A systematic x-ray magnetic circular dichroism study of the paramagnetic phase of ErCo2 has recently allowed to identify the inversion of the net magnetization of the Co net moment with respect to the applied field well above the…
The heavy-fermion compound URu2Si2 exhibits a hidden-order phase below the temperature, ~ 17.5 K. In spite of intense research for past three decades, no consensus on the order parameter exists and the nature has posed a long-standing…