The Magnetic Properties of 1111-type Diluted Magnetic Semiconductor (La<sub>1−<i>x</i></sub>Ba<sub><i>x</i></sub>)(Zn<sub>1−<i>x</i></sub>Mn<sub><i>x</i></sub>)AsO in the Low Doping Regime
oleh: Guoxiang Zhi, Kai Wang, Haojie Zhang, Cui Ding, Shengli Guo, Yilun Gu, Licheng Fu, F. L. Ning
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2018-11-01 |
Deskripsi
We investigated the magnetic properties of (La<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mrow> <mn>1</mn> <mo>−</mo> <mi>x</mi> </mrow> </msub> </semantics> </math> </inline-formula>Ba<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mi>x</mi> </msub> </semantics> </math> </inline-formula>)(Zn<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mrow> <mn>1</mn> <mo>−</mo> <mi>x</mi> </mrow> </msub> </semantics> </math> </inline-formula>Mn<inline-formula> <math display="inline"> <semantics> <msub> <mrow></mrow> <mi>x</mi> </msub> </semantics> </math> </inline-formula>)AsO with <i>x</i> varying from 0.005 to 0.05 at an external magnetic field of 1000 Oe. For doping levels of <i>x</i> ≤ 0.01, the system remains paramagnetic down to the lowest measurable temperature of 2 K. Only when the doping level increases to <i>x</i> = 0.02 does the ferromagnetic ordering appear. Our analysis indicates that antiferromagnetic exchange interactions dominate for <i>x</i> ≤ 0.01, as shown by the negative Weiss temperature fitted from the magnetization data. The Weiss temperature becomes positive, i.e., ferromagnetic coupling starts to dominate, for <i>x</i> ≥ 0.02. The Mn-Mn spin interaction parameter <inline-formula> <math display="inline"> <semantics> <mrow> <mo>∣</mo> <mn>2</mn> <mi>J</mi> <mo>/</mo> <msub> <mi>k</mi> <mi>B</mi> </msub> <mo>∣</mo> </mrow> </semantics> </math> </inline-formula> is estimated to be in the order of 10 K for both <i>x</i> ≤ 0.01 (antiferromagnetic ordered state) and <i>x</i> ≥ 0.02 (ferromagnetic ordered state). Our results unequivocally demonstrate the competition between ferromagnetic and antiferromagnetic exchange interactions in carrier-mediated ferromagnetic systems.