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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]

We have investigated the magnetic properties and the magnetocaloric effect of a GdCoO3−δ epitaxial thin film which was successfully grown on a (001) LaAlO3 substrate by a simple polymer assisted deposition (PAD) method. A paramagnetic–antiferromagnetic magnetic phase transition has been observed in the film at TN (Gd) = 3.2 K. This film exhibits a considerable magnetocaloric effect derived from the interaction between the localized 4f moment of Gd3+ (J = S = 7/2 and L = 0) ions with −ΔSM = 489.75 mJ K−1 cm−3 for a field change of 70 kOe at T = 3.5 K. The significant magnetic entropy change together with the large refrigerant capacity indicate that the GdCoO3−δ epitaxial thin film has potential for cryogenic magnetic cooling of microdevices and microsystems. [ABSTRACT FROM AUTHOR]

Magnetocaloric effect (MCE) in polycrystalline HoMn2O5 was investigated by isothermal magnetization curves from 2 K to 50 K. A relatively large magnetic entropy change, ΔSM = 7.8 J/(kg ·K), was achieved with the magnetic field up to 70 kOe (1 Oe = 79.5775 A · m-1). The magnetic entropy change is reversible in the whole range of temperature. The contributions of elastic and magnetoelastic energy to the changing of the magnetic entropy are discussed in terms of the Landau theory. The reversibility of MCE with maximal refrigerant capacity RC = 216.7 J/kg makes polycrystalline HoMn2O5 promising as a magnetic refrigerant. [ABSTRACT FROM AUTHOR]

Magnetocaloric effect (MCE) in polycrystalline HoMn2O5 was investigated by isothermal magnetization curves from 2 K to 50 K. A relatively large magnetic entropy change, ΔSM = 7.8 J/(kg ·K), was achieved with the magnetic field up to 70 kOe (1 Oe = 79.5775 A · m-1). The magnetic entropy change is reversible in the whole range of temperature. The contributions of elastic and magnetoelastic energy to the changing of the magnetic entropy are discussed in terms of the Landau theory. The reversibility of MCE with maximal refrigerant capacity RC = 216.7 J/kg makes polycrystalline HoMn2O5 promising as a magnetic refrigerant. [ABSTRACT FROM AUTHOR]

We have investigated the magnetic properties and magnetocaloric effects (MCEs) of R 2 Mo 2 O 7 ( R = Er, Dy, Gd and Y). Magnetic ground states of R 2 Mo 2 O 7 largely depend on the radius of rare earth ion. Er 2 Mo 2 O 7 , Dy 2 Mo 2 O 7 and Y 2 Mo 2 O 7 with small rare earth radius exhibit spin-glass state around 20 K, while Gd 2 Mo 2 O 7 with larger rare earth radius undergoes a ferromagnetic state below 78 K and a reentrant spin-glass behavior below 34 K. Magnetic phase transition leads to magnetocaloric effect. In particular, a natural table-like - Δ S M and a very large refrigerant capacity ( RC ) value of 94.4 J/kg was observed in a field change of 0–10.5 kOe for Gd 2 Mo 2 O 7 due to two successive magnetic transitions at ∼78 and ∼10 K. These notable magnetocaloric properties make the Gd 2 Mo 2 O 7 a potential candidate for low-field Ericsson-cycle magnetic refrigeration in the low temperature range. [ABSTRACT FROM AUTHOR]