Doping of Ga in antiferromagnetic semiconductor α-Cr2O3 and its effects on magnetic and electronic properties

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:432

Article

Bhowmik, R. N.¹  Siva, K. Venkata¹  Ranganathan, R.²  Mazumdar, Chandan² 

[1] Pondicherry Univ, Dept Phys, Pondicherry 605014, India

[2] Saha Inst Nucl Phys, Condensed Matter Phys Div, 1-AF Bidhannagar, Kolkata 700064, India

关键词: Magnetic semiconductor;    Tuning of band gap;    Negative differential resistance;    I-V loop, Bi-stable electronic state;   

DOI  :  10.1016/j.jmmm.2017.01.075

来源: Elsevier

【 摘 要 】

The samples of Ga-doped Cr2O3 have been prepared using chemical co-precipitation route. X-ray diffraction pattern and Raman spectra have indicated rhombohedral crystal structure with space group R (3) over barC. Magnetic measurements indicated diluted antiferromagnetic (AFM) spin order in Ga-doped alpha-Cr2O3 and ferrimagnetic ordering of spins at about 50-60 K is confirmed from the analysis of the temperature dependence of dc magnetization and ac susceptibility data. Apart from magnetic dilution effect, the samples have shown superparamagnetic behavior below 50 K due to frustrated surface spins of the nano-sized grains. The samples have shown non-linear electronic properties. The current-voltage (I-V) characteristics of the Ga-doped alpha-Cr2O3 samples are remarkably different from alpha-Cr2O3 sample. The bi-stable electronic states and negative differential resistance are some of the unique non-linear electronic properties that the I-V curves of Ga-doped samples have exhibited. Optical study revealed three electronic transitions in the samples associated with band gap energy at about 2.67-2.81 eV, 1.91-2.11 eV, 1.28-1.35 eV, respectively. The results indicated multi-level electronic structure in Ga-doped alpha-Cr2O3 system. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

Free