Magnetic phase transition and giant anisotropic magnetic entropy change in TbFeO3 single crystal

Abstract

The magnetocaloric effect (MCE) is an intrinsic property of magnetic materials that enable magnetic refrigeration devices without using the traditional vapour-compression. Temperature sensitive and anisotropic magnetic solids might give rise to a large rotating MCE for building compact and efficient magnetic cooling systems by simply rotating the sample. Here, we report an unprecedented maximal refrigeration capacity of 497.36 J/kg (at 70 kOe) in perovskite TbFeO3 single crystal, resulting from its giant anisotropic magnetic entropy change along a axis. Our paper reveals that interaction between Fe-3d and Tb-4f electrons drives extremely interesting spin reorientation transition, which is highly sensitive to magnetic field and temperature. These findings highlight potential applications of an emerging material for high efficient low temperature magnetic refrigeration, which is compact and quiet, and does not use ozone-depleting coolant gases.

Giant magnetocaloric effect in an exchange-frustrated GdCrTiO5 antiferromagnet

“…Several rare-earth element based transition metal oxides and intermetallic compounds carrying high magnetic moments have become attractive candidates for the low-temperature magnetic refrigeration. [21][22][23][24][25][26][27][28][29][30] In these materials, the rare-earth magnetic moments order at low temperature and a strong suppression of the magnetic entropy takes place in the vicinity of the order-disorder phase transition with the application of magnetic field. However, the value of the magnetic entropy, ∆S m , decreases rapidly and becomes very small just few Kelvin below the transition temperature and thereby limits the lowest temperature achievable by the magnetic refrigeration technique.…”

Far-IR magnetospectroscopy of magnons and electromagnons in TbFeO3 single crystals at low temperatures

“…(f x c y ) configuration[8,12]. As in the case with the temperature region (F x G z ) phase of Fe spins in both e b h c and e c h b configurations and its frequency gradually increases with the field increase till it saturates at 28 cm -1 in the field of 7 T [see Figs.4(c,f)] due to saturation of Tb moments.…”

“…At T=1.5 K application of magnetic field along the c-axis stabilizes 4 ( ) Γ (a x g y ) arrangement of Tb moments [10,12,13]. Figure 7 shows magnetic field (H||c) dependence of the normalized transmittance measured in the e a h b configuration at T=1.5 K. A single mode is observed with a linear increase of the frequency from ≈23 cm -1 at H=0 to 27 cm -1 at 0 5 T H μ = .…”

“…With further temperature decrease the Tb−Tb interaction leads to an antiferromagnetic ordering of Tb moments [7]. It was shown [4,8] It is also known that the external magnetic field H applied along a, b, and c axes results in an additional spin reorientation (SR) transitions that have been studied at low temperatures using magnetization methods [9,10,11,12], Mössbauer spectroscopy [11], neutron diffraction [13], magnetostriction [14] and sound velocity [8] measurements. Several anomalies have been found including the two-stage metamagnetic transitions for || H b at T < Tb N T .…”

“…Γ (G xz F zx ) phase in which the ferromagnetic vector F rotates from the c-axis towards the a-axis while the antiferromagnetic vector G rotates from the a axis towards c[8,12,14].Γ phase for Fe spins, the q-FM mode is active for h||(b,c) and, thus, it can be observed both in the e b h c and e c h b configurations, as shown in Figs. 4(a,d) with a saturated frequency of ~28 cm -1 in high magnetic fields.…”