Room-Temperature Epitaxial Growth of Ni-Zn Ferrite Thin Films by Pulsed Laser Deposition in High Vacuum

Abstract

Thin films of Ni-Zn ferrite have been epitaxially grown in situ on basal plane sapphires at room temperature by pulsed laser deposition in high vacuum. The films deposited at oxygen pressures of 1×10-5 to 1×10-6 Torr grew with spinel-type crystal structure and (111) planar orientation. X-ray phi scan analysis showed that the [110] direction in the (Ni, Zn)Fe2O4 (111) plane is parallel to the [1100] direction in the sapphire (0001) plane. The films exhibited streaky reflection high-energy electron diffraction patterns, indicating excellent surface smoothness.

Epitaxial Growth of Ni-Ferrite Thin Films by Pulsed Laser Deposition at Low Temperature

“…Consequently, the precipitation of the metal phase in the film is obviously ascribed to oxygen deficiency. On the other hand, the crystalline phase of the film deposited at P(02) of greater than 1 x 10- 6 Torr, where the low deposition rate guarantees the sufficient oxygenation of the ablated particles, was primarily dominated by the substrate tempera~ ture: The films deposited at T s :s; 100°C crystallized in the NaCl-type crystal structure, while at Ts ;? : 150°C, in the spinel-type crystal structure.…”

“…Omata et al reported that the polycrystalline films of NiZnferrite were obtained at temperature as low as 200°C on glass substrates by PLD [5]. We have recently found that NiZn-ferrite thin films were epitaxially grown on sapphire substrates even at room temperature using PLD in high vacuum [6]. These indicate the high potential of PLD for the low temperature growth of the ferrite thin films.…”

“…This technique has been previously successful in depositing oxide films, and in particular high-T e superconductors. The PLD of ferrite thin films at low temperatures has been reported by many researchers [1][2][3][4][5][6]. Dorsey et al demonstrated that the epitaxial thin films of Co-ferrite were grown at 200°C or more on MgO substrates by PLD [4J.…”

“…This is due to components vaporized from the target surface, mainly oxygen. The oxygen pressure P(02) was held between 1 x 10- 6 Torr and 1 x 10-2 Torr during deposition by introducing oxygen gas through a precision leak valve. The typical rate of the film deposition was 0.4 nm/min, much lower than those reported previously.…”

MICROWAVE DIELECTRIC PROPERTIES OF NI_0.2CU_XZN_0.8-XFE₂O₄ FOR APPLICATION IN ANTENNA

“…They have great potential as microwave materials because of their high resistivity, ease of fabrication as well as low eddy current losses and high saturation magnetization as compared with other ferrites [43][44][45][46][47][48]. Variations in the zinc concentration in these ferrites allow the tailoring of the magnetic properties to suit the requirement of a particular application [49].…”