Pressure dependence on the remanent magnetization of Fe-Ni alloys and Ni metal

Abstract

We measured the acquisition of magnetic remanence of iron-nickel alloys (Fe 64 Ni 36 , Fe 58 Ni 42 , and Fe 50 Ni 50 ) and pure Ni under pressures up to 23 GPa at room temperature. Magnetization decreases markedly for Fe 64 Ni 36 between 5 and 7 GPa yet remains ferromagnetic until at least 16 GPa. Magnetization rises by a factor of 2-3 for the other compositions during compression to the highest applied pressures. Immediately upon decompression, magnetic remanence increases for all Fe-Ni alloys while magnetic coercivity remains fairly constant at relatively low values (5-20 mT). The amount of magnetization gained upon complete decompression correlates with the maximum pressure experienced by the sample. Martensitic effects best explain the increase in remanence rather than grain-size reduction, as the creation of single domain sized grains would raise the coercivity. The magnetic remanence of low Ni Invar alloys increases faster with pressure than for other body-centered-cubic compositions due to the higher magnetostriction of the low Ni Invar metals. Thermal demagnetization spectra of Fe 64 Ni 36 measured after pressure release broaden as a function of peak pressure, with a systematic decrease in Curie temperature. Irreversible strain accumulation from the martensitic transition likely explains the broadening of the Curie temperature spectra, consistent with our x-ray diffraction analyses.

h-MBenes: Promising Two-Dimensional Material Family for Room-Temperature Antiferromagnetic and Hydrogen Evolution Reaction Applications

“…The enhanced T N of h -VB can be attributed to the reduction in distances between V atoms caused by the applied compressive strain. This phenomenon has been experimentally observed in Fe 64 Ni 36 alloy, where compressive strain strengthens ferromagnetic interactions by decreasing the distances between nearest neighbor Fe atoms …”

“…This phenomenon has been experimentally observed in Fe 64 Ni 36 alloy, where compressive strain strengthens ferromagnetic interactions by decreasing the distances between nearest neighbor Fe atoms. 71 The calculation results of ΔG H* for h-HfBO under different biaxial strains are presented in Figure 6e. It is observed that the adsorption of H* (hydrogen) on h-HfBO decreases as the biaxial compressive strain increases.…”

Interplay between chemical order and magnetic properties in L1$_0$ FeNi (tetrataenite): A First-Principles Study

“…If we simply scale the predicted values for T C of the chemically ordered case according to our obtained reduction of the ferromagnetic-paramagnetic energy difference, we obtain an estimate for the Curie temperature of chemically disordered FeNi of around 550 K, which however appears too low compared to experimental values of around 785-789 K [37,38].…”

Magnetism in the strained ordered phases of Pt x Fe 1-x and Pt x Co 1-x ( x =0.25, 0.5, and 0.75)

“…The temperature-dependent effects of pressure have also been seen in studies of the Curie temperature of Fe3Pt [10][11]. Studies have also been performed on the acquisition of magnetic remanence of iron-nickel alloys (Fe64Ni36, Fe58Ni42, and Fe50Ni50) and pure Ni under pressures up to 23 GPa [12]. In these studies strain may accumulate irreversibly throughout the system.…”