The magnetic and structural properties of pulsed laser deposited epitaxial Mn1−xZnxFe2O4 ferrite films (abstract)

Abstract

Since modern high frequency device technology is shifting towards planar miniaturization, ferrite films will play an important role in facilitating the design and fabrication nonreciprocal monolithic integrated devices such as isolators and circulators. The authors have examined magnetic and structural properties for a series of pulsed laser deposited (PDL) single crystal MnZn-ferrite films. The films were epitaxially grown on (001) MgO at substrate temperatures of 300 °C, 400 °C, 600 °C, and 800 °C in an oxygen partial pressure of 30 mTorr. The film microstructure, crystal structure, and composition were characterized by SEM, x-ray diffraction and atomic absorption spectroscopy, respectively. The magnetocrystalline anisotropy constant K1, uniaxial anisotropy constant Ku, saturation magnetization Ms, and coercive force Hc were examined by torque and vibrating sample magnetometry. Ferrimagnetic resonance measurements were made on the films to obtain the linewidth ΔH. A comparison of the magnetic, structural, and chemical properties shows that K1 and Ms scale with the Fe2+ ion concentration and that Ku, Ms, and ΔH are very sensitive to the microstructure. The values of K1, Ms, and ΔH obtained for films deposited at 800 °C were compared with those of bulk MnZn-ferrite and found to exceed the bulk values (Table I), thus making PLD ferrite films very attractive for nonreciprocal device applications.