采用标准固相反应法制备了La0.45Ca0.55Mn1-xO3(x=0.00,0.06,0.10,0.12)多晶样品.通过XRD、ρ-T曲线、M-T曲线和ρ-T拟合曲线,研究了Mn位V5+离子掺杂对体系的电荷有序相及输运性质的影响.实验结果表明:随着V5+离子的掺杂量的增加,电荷有序相(CO)逐渐削弱,当x=0.10时,CO相基本融化但还有部分残留,当x=0.12时CO相完全融化;对低掺杂(x=0.00,0.06)样品,表现出复杂磁相:随温度降低,发生顺磁-电荷有序-反铁磁相变,40 K附近,在反铁磁背景下产生再入型自旋玻璃态;随掺杂量增加,体系的电阻率逐渐减小,当掺杂量x≥0.10时,样品发生金属-绝缘体相变,其相变温度随着掺杂量的增加而向高温移动.对于金属型导电机制满足自旋波散射和电-磁子之间的散射,而绝缘体导电机制有两种情况:x≤0.10的样品满足变程跃迁模型ρ=ρ0exp(T0/T) 1/4,x=0.12的样品则满足小极化子绝热最近邻跃迁模型ρ=ATexp(Eα/κBT),通过掺杂实现了从变程跃迁到绝热小极化子最近邻跃迁.
参考文献
| [1] | Helmolt R V;Weeker J;Holzapfel B;Schultz L Samwer K .Giant negative magnetoresistance in perovskitelike La2/3 Ba1/3 MnOx ferromagnetic films[J].Physical Review Letters,1993,71:2331. |
| [2] | Liu G L;Zhou J S;Goodenough J B .Competing magnetic pha-ses in mixed-valent manganese oxide perovskites[J].Physical Review B:Condensed Matter,2004,70:224421. |
| [3] | 王闻琦,彭振生,严国清,毛强.稀土双掺杂锰氧化物La0.5Dy0.2Sr0.3MnO3的磁性质[J].稀有金属,2008(01):46-49. |
| [4] | Salamon MB.;Jaime M. .The physics of manganites: Structure and transport [Review][J].Reviews of Modern Physics,2001(3):583-628. |
| [5] | Millis A J;Lirrlewood P B;Shraiman BL .Double exchange a-lone does not explain the resistivity of La1-xSrxMnO3[J].Physical Review Letters,1995,74:5144. |
| [6] | Popovic Z.;Satpathy S. .Origin of charge-orbital order in the half-doped manganites - art. no. 197201[J].Physical review letters,2002(19):7201-0. |
| [7] | Mutou T.;Kontani H. .Charge-orbital stripe structure in La1-xCaxMnO3 (x=1/2, 2/3)[J].Physical review letters,1999(18):3685-3688. |
| [8] | Yunoki S.;Dagotto E.;Hotta T. .Ferromagnetic, A-type, and charge-ordered CE-type states in doped manganites using Jahn-Teller phonons[J].Physical review letters,2000(16):3714-3717. |
| [9] | PENG Zhensheng,GUO Huanyin,YAN Guoqing,MAO Qiang.Research on charge ordering and magnetic properties in La0.3Ca0.7Mn1-xWxO3 system[J].稀有金属(英文版),2007(04):317-322. |
| [10] | 刘宁,严国清,蔡之让,郭焕银,彭振生,曲哲,张裕恒.La0.3Ca0.7Mn1-xWxO3体系的电荷序和自旋序[J].科学通报,2005(18):1942-1947. |
| [11] | 蔡之让,郭焕银,刘宁,张裕恒.La0.3Ca0.7Mn1-xWxO3体系电荷有序的建立与融化[J].光谱学与光谱分析,2007(02):223-227. |
| [12] | 彭振生,郭焕银,严国清,毛强.钙钛矿锰氧化物La0.3Ca0.7Mn0.96W0.04O3在电荷有序相中的磁性质[J].稀有金属,2006(05):635-638. |
| [13] | Vanitha PV.;Natarajan S.;Rao CNR.;Singh RS. .Distinction between two types of charge-ordered states in the rare earth manganates, Ln(0.5)A(0.5)MnO(3), based on chemical melting[J].International Journal of Quantum Chemistry,1998(2):365-368. |
| [14] | Maignan A.;Barnabe A.;Martin C.;Hervieu M.;Raveau B.;Damay F. .The effect of Mn-site doping on the magnetotransport properties of CMR manganites[J].Philosophical transactions of the Royal Society. Mathematical, physical, and engineering sciences,1998(1742):1635-1658. |
| [15] | Dagotto E.;Moreo A.;Hotta T. .Colossal magnetoresistant materials: The key role of phase separation [Review][J].Physics Reports: A Review Section of Physics Letters (Section C),2001(1/3):1-153. |
| [16] | 朱永文,方军,黄真,高秉钧.（La1-x Yx）0.5Sr0.5MnO3体系的结构和输运性质研究[J].低温物理学报,2003(02):151-156. |
| [17] | 刘宁,孙阳,张裕恒.Mechanism of Insulator-Metal Transition in La2/3 Ca1/3MnO3: Collapse of Small Polaron[J].中国物理快报(英文版),2001(07):957-959. |
| [18] | Deteresa JM.;Blasco J.;Garcia J.;Marquina C.;Algarabel PA. Arnold Z.;Kamenev K.;Ritter C.;Vonhelmolt R.;Ibarra MR. .SPONTANEOUS BEHAVIOR AND MAGNETIC FIELD AND PRESSURE EFFECTS ON LA2/3CA1/3MNO3 PEROVSKITE[J].Physical Review.B.Condensed Matter,1996(2):1187-1193. |
| [19] | Mandal P.;Haupt L.;Poddar A.;von Helmolt R.;Jansen AGM. Wyder P.;Barner K. .High-field magnetotransport properties of La2/3Sr1/3MnO3 and Nd2/3Sr1/3MnO3 systems[J].Physical Review.B.Condensed Matter,1998(17):10256-10259. |
| [20] | 彭振生,唐永刚,严国清,郭焕银,毛强.La0.67Sr0.08Na0.25MnO3的奇特输运性质及CMR效应[J].物理学报,2007(03):1707-1712. |
上一张
下一张
上一张
下一张
计量
- 下载量()
- 访问量()
文章评分
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%