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The structural, magnetic and magnetocaloric effect (MCE) properties were studied in DyCoO3 nanoparticles. The synthesized DyCoO3 nanoparticles were approximately 200 nm in size with a typical orthogonal perovskite structure. DyCoO3 possesses an antiferromagnetic ordering at TN = 3.9 K. In magnetic field changes of 0–60 kOe, a giant maximum magnetic entropy change of 16.6 J/kg K and a relative cooling power of 354 J/kg were obtained around TN. These results suggest that DyCoO3 nanoparticles could be regarded as promising candidate for low temperature magnetic refrigerants. [ABSTRACT FROM AUTHOR]

We investigate the ultrafast spin dynamics of an antiferromagnet in a ferromagnet/antiferromagnet heterostructure Fe/GdFeO3 via an all-optical method. After laser irradiation, the terahertz spin precession is hard to be excited in a bare GdFeO3 without spin reorientation phase but efficiently in Fe/GdFeO3. Both quasi-ferromagnetic and impurity modes, as well as a phonon mode, are observed. We attribute it to the optical modification of interfacial exchange coupling between Fe and GdFeO3. Moreover, the excitation efficiency of dynamics can be modified significantly via the pump laser influence. Our results elucidate that the interfacial exchange coupling is a feasible stimulation to efficiently excite terahertz spin dynamics in antiferromagnets. It will expand the exploration of terahertz spin dynamics for antiferromagnet-based opto-spintronic devices. [ABSTRACT FROM AUTHOR]