First Observation of Low-Temperature Magnetic Transition in CuAgSe

In this Article, the temperature-dependent magnetic properties of CuAgSe pellet sintered from surfactant-free CuAgSe nanoparticles synthesized by a wet chemistry method were investigated in the temperature range of 4-300 K. A magnetic transition between diamagnetism and weak ferromagnetism is observed at around 60-70 K. The results from magnetic measurements under different machines/magnetic fields, room-Temperature X-ray photoelectron spectroscopy, and temperature-dependent nuclear magnetic resonance all demonstrate that this magnetic transition is an intrinsic property rather than an effect of impurities. Combining these results with temperature-dependent neutron diffraction, the origin of the weak ferromagnetism is ascribed to a structural crossover-induced canted antiferromagnetism and possible deviation of Cu valence. The transition is strongly dependent on the sintering temperature and pressure, which could induce the structural phase transition.