Observation of room temperature ferromagnetism in nanocrystalline ZnO: Co system

被引：36

作者：

Bhatti, Kanwal Preet ^{[1
]}

Kundu, Shankhamala ^{[1
]}

Chaudhary, Sujeet ^{[1
]}

Kashyap, Subhash C. ^{[1
]}

Pandya, Dinesh K. ^{[1
]}

机构：

[1] Indian Inst Technol, Dept Phys, Thin Film Lab, New Delhi 110016, India

来源：

JOURNAL OF PHYSICS D-APPLIED PHYSICS | 2006年 / 39卷 / 23期

关键词：

D O I：

10.1088/0022-3727/39/23/001

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Nanocrystalline ZnO : Co samples (having 5 at.% Co) exhibiting room temperature ferromagnetism (RTFM) have been synthesized from acetate precursors. The effect of sequential sintering of the samples at higher temperatures for prolonged duration in air ambient has been investigated for their phase-purity and magnetic characteristics. The nanocrystalline ZnO : Co obtained after calcinations at 600 degrees C exhibits RTFM. The study further indicates that the Co3O4 phase progressively forms with increasing sintering temperature, and partially transforms into CoO at and above 800 degrees C. Irrespective of the sintering temperature and duration, the samples sintered at and above 800 degrees C exhibited identical magnetization behaviour with regard to the saturation moment and field required for technical saturation. The ferromagnetism persisting even at higher temperatures (>= 800 degrees C) arises intrinsically in the insulating Zn1-x CoxO phase. The recently proposed bound magnetic polaron model appears to account for the observed ferromagnetic ordering in this carrier deficient oxide system. A paramagnetic contribution to the overall magnetization is also observed, which is attributed to the paramagnetic Co3O4 and CoO and possibly to isolated polarons and/or non-interacting Co2+ ions.

引用

页码：4909 / 4914

页数：6