Metamagnetic transitions in cubic La(Fe_xAl_1-x)₁₃ intermetallic

Cubic NaZn₁₃-type compounds of the form La(Fe_xAl_1-x)₁₃ was stabilised with compositions between LaFe₆Al₇. For compositions above LaFe_11.2Al_1.8 (x=0.861) a low-temperature antiferromagnetic state is present in small external fields. However, upon increasing the field to a few tesla, an exceedingly sharp spin-flip transition with remarkably large hysteresis occurs to the fully saturated ferromagnetic state. The origins of this unusual metamagnetic transition are discussed in terms of the special crystal structure.