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La0.5Pr0.5Mn2Si2 undergoes an antiferromagnetic-ferromagnetic transition at about 250 K (C). This transition can also be induced by an external magnetic field leading to a metamagnetic transition. This can lead to a large change in the magnetic entropy, which is useful for magnetic cooling and studying the magnetocaloric effect. We investigated the details of the spin configuration as the magnetic ordering progresses from AF to FM by neutron diffraction techniques under magnetic fields up to 5 T and using spectral refining methods. (C) The Minerals, Metals & Materials Society and ASM International 2017

Fe3C incorporates only Fe as a metallic element and is an Invar material with valence electron concentration 8.67. We have studied the equation of state up to 20 GPa of Fe3C particles sd ,40 nmd below and above the Curie temperature (room temperature and 550 K, respectively) to search for a softening associated with a magnetovolume instabilities characteristic of Invar-type material. The isothermal bulk modulus of Fe3C particles at room temperature was found to be about 13% smaller than that of the value at 550 K. This difference is comparable with the relative difference in the bulk modulus of Fe65Ni35 Invar in a similar temperature range around the Curie temperature.

The structural and magnetic properties of stoichiometric Ni2MnAl are studied to clarify the conditions for ferromagnetic and antiferromagnetic ordering claimed to occur in this compound. X-ray and magnetization measurements show that although a single phase B2 structure can be stabilized at room temperature, a single L21 phase is not readily stabilized, but rather a mixed L21+B2 state occurs. The mixed state incorporates ferromagnetic and antiferromagnetic parts for which close-lying Curie and a Neel temperatures can be identified from magnetization measurements.