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A comparative study of the effect of Fe and Ni doping on the bismuth based perovskite La0.6Bi0.4MnO3.1, a projected spintronics magnetic semiconductor has been carried out. The doped systems show an expressive change in magnetic ordering temperature. However, the shifts in ferromagnetic transition (TC) of these doped phases are in opposite direction with respect to the parent phase TC of 115 K. The Ni-doped phase shows an increase in TC ~200 K, whereas the Fe-doped phase exhibits a downward shift to TC~95 K. Moreover, the Fe-doped is hard-type whereas the Ni-doped compound is soft-type ferromagnet. It is observed that the materials are semiconducting in the ferromagnetic phase with activation energies of 77 & 82 meV for Fe & Ni-doped phases respectively. In the presence of external magnetic field of 7 Tesla, they exhibit minor changes in the resistivity behaviours and the maximum isothermal magnetoresistance is around -20 % at 125 K for the Ni-phase. The results are explained on the basis of electronic phase separation and competing ferromagnetic and antiferromagnetic interactions between the various mixed valence cations.
Ni$_{80}$Fe$_{20}$ (Py) and Py-Cu exhibit intriguing ultrafast demagnetization behavior, where the Ni magnetic moment shows a delayed response relative to the Fe [S. Mathias et al., PNAS {bf 109}, 4792 (2012)]. To unravel the mechanism responsible fo
The magnetocaloric effect (MCE) in paramagnetic materials has been widely used for attaining very low temperatures by applying a magnetic field isothermally and removing it adiabatically. The effect can be exploited also for room temperature refriger
We present measurements of interfacial Gilbert damping due to the spin pumping effect in Ni$_{81}$Fe$_{19}$/W heterostructures. Measurements were compared for heterostructures in which the crystallographic phase of W, either $alpha$(bcc)-W or $beta$(
We have studied the effect of Fe addition on the structural and magnetic transitions in the magnetic shape memory alloy Ni-Mn-Ga by substituting systematically each atomic species by Fe. Calorimetric and AC susceptibility measurements have been carri
Using low-temperature molecular beam epitaxy, we study substitutions of Fe atoms for Co ones in Co_3-xFe_xSi Heusler-compound films grown on Si and Ge. Even for the low-temperature grown Heusler-compound films, the Co-Fe atomic substitution at A and