Dielectric, magnetic, and lattice dynamics properties of Y-type hexaferrite Ba0.5Sr1.5Zn2Fe12O22: Comparison of ceramics and single crystals

Abstract

We prepared multiferroic Y-type hexaferrite Ba0.5Sr1.5Zn2Fe12O22 ceramics and compared their magnetic and dielectric properties with single crystal. Magnetic susceptibility and microwave resonance measurement revealed magnetic phase transition at TC=312 K, similar as in single crystal. Ferroelectric (FE) phase can be induced by external magnetic field in all investigated samples and the phase diagram in ceramics qualitatively resembles that of the single crystal. The range of magnetic fields, where the FE phase is induced, broadens after annealing of single crystal. Ceramics quenched after sintering exhibit several orders of magnitude lower conductivity than the single crystal. Heavily damped magnetic resonance was discovered in terahertz spectra at 10 K and its frequency softens below 5 GHz near TC. Number and symmetry of observed infrared (IR) and Raman active phonons correspond to paraelectric phase with D3d5 hexagonal structure. No evidence for a structural phase transition was found in the IR and Raman spectra on cooling (in zero magnetic field) or in the room-temperature IR spectra with external static magnetic field up to 0.3 T.

Large reversible room-temperature magnetocaloric effect in the Ba0.5Sr1.5Zn2Fe12O22-related hexaferrites

“…For BSZFO-00, there exists a sharp peak at $ 300 K, which is defined as T N . This transition temperature of 300 K is very close to that ($ 312 K) reported previously in polycrystalline ceramics [20], but is somewhat lower than the ferrimagnetic state to paramagnetic transition temperature ($ 337 K) reported in BSZFO-00 single crystal [21], which might be ascribed to the different sample preparation process. For BSZMFO or BSZCFO, the T N (listed in Table 1) increased to higher temperatures, which is due to the increased lattice distortion by the substitution of smaller ion Mg or Cu for the Zn ion.…”

Magnetocaloric effect in multiferroic Y-type hexaferrite Ba0.5Sr1.5Zn2(Fe0.92Al0.08)12O22

“…23 However, the M-H curves show triple loops at 200 K, and it increases in two steps up to the saturation magnetization, which hints that several successive metamagnetic transitions take place with increasing magnetic field, such as modified screw, intermediate-I, -II, -III, and ferromagnetic ordered states. 24,27 The similar results were also reported in single-crystal Ba 0.5 Sr 1.5 Zn 2 Fe 12 O 22 . 16,24 Figure 3(a) shows isothermal magnetization curves of BSZFAO under the magnetic field up to 7 T from 5 K to 800 K. The saturation magnetization is suppressed with increasing temperature.…”

Electric and magnetic properties of Y-type Ba2Mg2Fe12O22 hexaferrites with various Co doping

“…Up to now, many investigations have been focused on the dielectric properties and conductivity properties of Y-type hexaferrite, such as the Zn 2 Y hexaferrite [19,20], Co 2 Y hexaferrite [21][22][23], and Ni 2 Y hexaferrite [10,13,24]. However, there is few work related to the dielectric and conductivity properties of Mg 2 Y hexaferrite.…”