Magnetic and optical properties of MgAl2O4-(Ni0.5Zn0.5)Fe2O4 thin films prepared by pulsed laser deposition

Takeshi Misu; Naonori Sakamoto; Kazuo Shinozaki; Nobuyasu Adachi; Hisao Suzuki; Naoki Wakiya

doi:10.1088/1468-6996/12/3/034408

Magnetic and optical properties of MgAl₂O₄-(Ni_0.5Zn_0.5)Fe₂O₄ thin films prepared by pulsed laser deposition

Sci Technol Adv Mater. 2011 May 27;12(3):034408. doi: 10.1088/1468-6996/12/3/034408. eCollection 2011 Jun.

Authors

Takeshi Misu¹, Naonori Sakamoto¹, Kazuo Shinozaki², Nobuyasu Adachi³, Hisao Suzuki⁴, Naoki Wakiya¹

Affiliations

¹ Department of Materials Science and Chemical Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8561, Japan.
² Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550, Japan.
³ Ceramics Research Laboratory, 10-6-29, Asahigaoka, Tajimi, Gifu 507-0071, Japan.
⁴ Graduate School of Materials Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8561, Japan.

Abstract

Thin films composed of MgAl₂O₄ and (Ni_0.5Zn_0.5)Fe₂O₄ ([MA(100-x)-NZFx] films) were grown on fused SiO₂ substrates by pulsed laser deposition. X-ray diffraction measurements revealed that the films were polycrystalline, and that their lattice constant varied linearly with composition, indicating the formation of a solid solution. The film with x=60 was paramagnetic and those with x ≥ 70 were ferromagnetic. The films had a transparency above 75% in the visible range, but the transparency decreased with the x value. The optical band gaps were 2.95, 2.55, 2.30 and 1.89 eV for x=20, 40, 60, 80 and 100, respectively. The Faraday rotation angle increased with x in the visible range, and the film with x=70 exhibited a value of 2000 degrees cm^-1 at 570 nm, which is comparable to the rotation angle of Y₃Fe₅O₁₂. Owing to their high transparency, which extends into the visible range, the [MA(100-x)-NZFx] films can be used in novel magneto-optical devices.

Keywords: Faraday rotation angle; pulsed laser deposition (PLD); solid solution of nickel zinc ferrite and magnesium aluminum spinel; transparent magnetic thin film.