Tunable magnetic phase transition in thulium–samarium orthoferrite single crystals

Spintronics and condensed matter physics are in pursuit of materials that can serve as carriers for novel quantum devices. Antiferromagnetic rare earth orthoferrites (RFeO3, where R is rare earth or Y), are potential functional materials for magnetic information processing. They exhibit temperature-controlled spin reorientation transition (SRT) and magnetic field/temperature-induced spin switching (SSW) properties. As such, RFeO3 is expected to be used in spintronic devices that can easily control the spin. With the advancement of research, the co-doping of rare earth ions has emerged as a prominent area of investigation in RFeO3. In this work, we have grown a series of Tm1-xSmxFeO3 (TSFO, x = 0, 0.2, 0.3, 0.4) single crystals via a four-mirror optical floating zone furnace. Crystal axes and single phase of these single crystals were determined using Laue back reflection camera and X-ray diffractometer. We observed that the doping of Sm ions can effectively regulate the spin reorientation temperature of the parent material TmFeO3. Both type-I and type-II SSW have been observed when the doping rate x is 0.2 or 0.4, perfectly integrating the magnetic properties of TmFeO3 and SmFeO3 single crystals. Furthermore, the spin switching in TSFO (x = 0.2, 0.3, 0.4) can be manipulated by applying low magnetic fields with tens of Oe. On the other hand, when the doping rate x reaches 0.4, the magnetic compensation phenomenon and the Néer temperature of rare earth ions occurred. The super-exchange interaction between R3+ and Fe3+ magnetic sublattices leads to these interesting phenomena.