Multiferroic properties in terbium orthoferrite

Multiferroic properties in a polycrystalline terbium orthoferrite are investigated. Different thermomagnetic behaviors are observed in different magnetic fields, which is attributed to the suppression of the low temperature magnetic phase by an external magnetic field. Further studies reveal that the ferroelectricity originates from the spin configuration below 3.5 K. In addition, the magnetic field control of electric polarization and dielectric constant is observed, which suggests a magnetoelectric effect in TbFeO3. The origin of ferroelectricity in this rare-earth orthoferrite is discussed.

Multiferroic properties and exchange bias in Bi_(1-x)Sr_xFeO_3(x=0–0.6) ceramics

Multiferroic properties and exchange bias （EB） in Bi1-xSrxFeO3 （x = 0-0.6） ceramics synthesized by a modified Pechini method are investigated. Sr concentration dependence of structure distorting, ferroelectric properties, and dielectric properties were studied at room temperature. Appropriate Sr doping （x = 0.05-0.2） has been found to decrease the conductivity, enhance ferroelectric properties and give rise to high dielectric constant. Compared with antiferromagnetic BiFeO3 compound, BSFO-x （O≤x ≤0.4） ceramics show weak ferromagnetism at room temperature, and their exchange bias field and vertical magnetization shift are observed and exhibit a strong dependence on the content of Sr. This observed EB effect which keeps stable in BSFO ceramics at 10 K tend to vanish at room temperature with Sr concentration over 0.4.

Modulation of magnetic properties and enhanced magnetoelectric effects in MnW_(1-x)Mo_xO_4 compounds

In this letter, we investigate the magnetic and ferroelectric properties of polycrystalline MnW1-xMoxO4 （x = 0, 0.05, 0.10, 0.20） compounds. The substitution of nonmagnetic Mo6＋ ions for W6＋ ions modifies the magnetic transition tem- peratures of MnW1-xMoxO4 by changing the Mn-O-Mn bond. As a result, distinct ferroelectric properties and enhanced magnetoelectric effects are observed in Mo6＋-doped MnWO4 compounds. The effects of substitution of Mo6＋ ions on magnetic properties and magnetoelectric coupling are discussed.

SYNTHESIS OF CoFe_(2)O_(4)/Pb(Zr_(0.53)Ti_(0.47))O_(3)MULTIFERROIC COMPOSITE THICK FILMS BY LOW-SINTERING-TEMPERATURE SCREEN PRINTING METHOD

CoFe_(2)O_(4)/Pb(Zr_(0.53)Ti_(0.47))TO_(3)(abbreviated as CFO/PZT)multiferroic composite thick films were successfully fabricated on alumina substrate with gold bottom electrode by screen printing method at a low-sintering temperature.The processing included the modi fication and dispersion of ferromagnetic CFO powder and ferroelectric PZT powder,the preparation of uniform pastes,and the selection of proper annealing temperature for composite thick films.Transmission electron microscopic pictures(TEM)indicated the submicron meter of particles size for both CFO and PZT particles.After annealing at 900℃ for 1 h in air,tape test con firmed the quality of multiferroic thick films as well as pure CFO and PZT films.X-ray diffraction(XRD)showed a coexistence of CFO and PZT phases;furthermore,a smooth surface was observed through scanning electron microscopic(SEM)pictures along with the sharp cross-sectional picture,indicative of 100
m of film thickness.Ferromagnetic and ferroelectric properties were observed in CFO/PZT films simultaneously at room temperature.Compared with the reported CFO/PZT multiferrroic thin films,the present ferromagnetic property was closing to that of the chemical solgel synthesized film and even that from the physical pulsed laser deposition technique.However,the ferroelectric property showed a degenerated behavior,possible reasons for this was discussed and further optimization was also proposed for the potential multifunctional application.

Ferroelectricity induced by non-symmetry of A-site cations in hexagonal antiferromagnetic In_(1-x)Yb_(x)FeO_(3)(x=0.1,0.2,0.3) perovskites

A new series of multiferroic In_(1-x)Yb_(x)FeO_(3)(x=0.1,0.2,0.3) compounds were prepared using the traditional synthesis method for the first time.Partially substituting In ions in InFeO3with Yb ions results in the weak ferroelectricity of the compound.A dielectric relaxation peak is found at ~500 K in the temperature dependence of the dielectric properties of the resulted compounds.The dielectric constant of In_(0.8)Yb_(0.2)FeO_(3)displays an anomaly at -500 K,and the ferroelectric hysteresis loop reveals its weak ferroelectric behaviors below this temperature.Similarly to InFeO_(3),the compounds crystallize in space group P63/mmc.The increase in the Yb content leads to an increment in a and a reduction in c parameters.The temperature dependence of magnetization for In_(0.8)Yb_(0.2)FeO_(3)gives a Néel temperature of -150 K.The hysteresis loops at 10 and 100 K indicate its weak ferromagnetic characteristics above room temperature.Thus,In_(1-x)Yb_(x)FeO_(3)(x=0.1,0.2,0.3) compounds show both weak ferroelectricity and weak ferromagnetism.The non-symmetry of Yb cations causes the ferroelectricity of the compounds.