Anomalous Magnetism in Epitaxial Mn2RuxGa Thin Films

Thin films of Mn 2 Ru x Ga grown by sputtering at low temperature, T sub = 225 ^◦ C, are nearly defect free and have in-plane grain size exceeding 180 nm. A higher T sub of 425 ^◦ C leads to an increased density of defects and reduced in-plane coherence. The near-perfect films grown at low temperature exhibit a pinched wasp-waist magnetic hysteresis that is a consequence of the frustration induced by exchange interaction and site-specific anisotropy. At higher temperatures, the long-range crystalline order is broken by the presence of defects and simpler square hysteresis loops are recovered.