Al3+掺杂对La0.8Sr0.2Mn1-xAlxO3电输运性能的影响

doi:10.15541/jim20220412

摘要/Abstract

摘要：

钙钛矿锰氧化物La_1–_xSr_xMnO₃(LSMO)作为一种代表性庞磁阻材料, 在磁传感器等领域具有广阔的应用前景, 但在低磁场和室温下很难获得显著的庞磁阻效应。为提高LSMO磁电阻效应和转变温度, 本研究采用传统固相反应法制备了La_0.8Sr_0.2Mn_1–_xAl_xO₃(0≤x≤0.25)(LSMAO)多晶样品, 并系统分析了Al³⁺掺杂对LSMO电输运性质和磁电阻效应的影响。X射线衍射(XRD)图谱表明LSMAO样品具有单一的菱方结构, 属于$\text{R}\bar{3}\text{C}$空间群。电输运性质研究发现, 样品的电阻率随Al³⁺的掺杂呈指数型上升, 且外加磁场使金属-绝缘体转变温度有所提高。这可能是由于Al³⁺稀释了Mn³⁺/Mn⁴⁺离子网络, 在减少载流子数量的同时增加了磁无序。此外, LSMAO陶瓷的导电机理随Al³⁺的掺杂从小极化子模型(Small polaron hopping model, SPH)转变成变程跳跃模型(Variable range hopping model, VRH), 说明非磁性的Al³⁺抑制了铁磁团簇间的载流子交换, 使得小极化子热激活近邻跃迁过程被抑制。LSMAO的磁电阻效应从21.03% (x=0)增大到59.71% (x=0.25), 证明Al³⁺掺杂可有效增强LSMAO的磁电阻效应。

关键词: 电输运, 小极化子模型, 变程跳跃模型, 磁电阻效应

Abstract:

As a colossal magnetoresistance material, the perovskite manganese oxide La_1–_xSr_xMnO₃ (LSMO) has broad application prospects in magnetic sensors and other fields. However, it is difficult to obtain a significant colossal magnetoresistance effect at a low magnetic field at room temperature. To improve its magnetoresistance effect and transition temperature, La_0.8Sr_0.2Mn_1–_xAl_xO₃(0≤x≤0.25) (LSMAO) polycrystalline samples were prepared by traditional solid-state reaction method in present work. Effects of Al³⁺ doping on the electrical transport property and magnetoresistance of LSMO were systematically analyzed. The X-ray diffraction (XRD) results indicate that all samples crystallize in a single rhombohedral structure with the space group of $\text{R}\bar{3}\text{C}$. Result of electrical transport property shows that resistivity of the samples increases exponentially with the increment of Al³⁺ doping amount, and the metal-insulator transition temperature is increased by an external magnetic field. This phenomenon may be attributed to dilution of the Mn³⁺/Mn⁴⁺ ions network by Al³⁺, which increases the magnetic disorder but reduces the number of carriers. In addition, the conduction mechanism of LSMAO ceramics change from the small polaron hopping model (SPH) to the variable range hopping model (VRH) after doping of Al³⁺, reflecting that the non-magnetic Al³⁺ weakens the carrier exchange between the ferromagnetic clusters. As a result, the thermally activated neighbor transition of small polarons is suppressed. Magnetoresistance effect of LSMAO is enhanced from 21.03% to 59.71% with x increasing from 0 to 0.25, which proves that the doping of Al³⁺can effectively enhance the magnetoresistance effect of LSMAO.

Key words: electrical transport, small polaron hopping model, variable range hopping model, magnetoresistance effect

中图分类号:

TQ174

张爱梅, 朱佳佳, 方天诚, 潘茜茜. Al³⁺掺杂对La_0.8Sr_0.2Mn_1-_xAl_xO₃电输运性能的影响[J]. 无机材料学报, 2023, 38(2): 148-154.

ZHANG Aimei, ZHU Jiajia, FANG Tiancheng, PAN Xixi. Effects of Al³⁺ Doping on the Structure and Electrical Transport Property of La_0.8Sr_0.2Mn_1-_xAl_xO₃[J]. Journal of Inorganic Materials, 2023, 38(2): 148-154.

图/表 8

图1 La0.8Sr0.2Mn1-xAlxO3 (0≤x≤0.25) 的XRD图谱和晶体结构

Fig. 1 XRD patterns and crystal structure of La0.8Sr0.2Mn1-xAlxO3 (0≤x≤0.25) (a) XRD patterns of La0.8Sr0.2Mn1-xAlxO3 (0≤x≤0.25); (b) Representatively-refined XRD pattern of La0.8Sr0.2Mn0.25Al0.75O3; (c) Crystal structure of LSMAO perovskite with red balls representing O, green balls representing La, and randomly distributed Mn and Al ions in the middle of the oxygen cage; Colorful figures are available on website

表1 XRD Rietveld精修的La0.8Sr0.2Mn1-xAlxO3 (0≤x≤0.25)晶格常数及精修数据

Table 1 Lattice constants and refined data of La0.8Sr0.2Mn1-xAlxO3 (0≤x≤0.25) obtained by XRD Rietveld refinement

x	a/nm	b/nm	c/nm	Volume/nm³	R_wp	R_p	Mn-O-Mn/(°)	Mn-O/nm	t_G	Grain size/nm
0	0.5526	0.5526	1.3365	0.35355	0.1589	0.1116	164.121	0.19646	0.97093	42.3
0.05	0.5521	0.5521	1.3357	0.35262	0.1754	0.1259	164.123	0.19628	0.97358	43.9
0.10	0.5509	0.5509	1.3339	0.35068	0.1764	0.1254	164.127	0.19592	0.97624	44.2
0.15	0.5504	0.5504	1.3334	0.34993	0.1692	0.1205	164.129	0.19578	0.97892	45.7
0.20	0.5492	0.5492	1.3319	0.34801	0.0858	0.0591	164.135	0.19542	0.98161	57.9
0.25	0.5481	0.5481	1.3304	0.34619	0.0759	0.0535	164.140	0.19508	0.98431	59.2

图2 在外加磁场0和3 T下La0.8Sr0.2Mn1-xAlxO3的电阻率-温度曲线

Fig. 2 Resistivity-temperature curves of La0.8Sr0.2Mn1-xAlxO3 under the applied magnetic field of 0 and 3 T (a) x=0; (b) x=0.05; (c) x=0.10; (d) x=0.15; (e) x=0.20; (f) x=0.25

图3 La0.8Sr0.2Mn1-xAlxO3 (0.1≤x≤0.25)在外加磁场0和3 T下高温区(lnρ~T-0.25)曲线的模型拟合

Fig. 3 Model fittings of the curves of La0.8Sr0.2Mn1-xAlxO3 (0.1≤x≤0.25) in the high temperature region (lnρ~T-0.25) under the applied magnetic field of 0 and 3 T (a-b) Small polaron hopping model; (c-h) Variable range hopping model

表2 La0.8Sr0.2Mn1-xAlxO3 (0≤x≤0.05)的低温金属相拟合结果

Table 2 Fitting results of low temperature metal phase for La0.8Sr0.2Mn1-xAlxO3 (0≤x≤0.05)

Al contents (Magnetic field)	ρ₀/(×10^-2, Ω·m)	ρ₂/(×10^-7, Ω·m·K^-2)	ρ_4.5/(×10^-13, Ω·m·K^-4.5)	ρ_e/(×10^-2, Ω·m·K^-0.5)	ρ_p/(×10^-14, Ω·m·K^-5)	ρ_s/(×10^-2, Ω·m)
x=0.00 (0 T)	-1.794	3.485	-5.435	-0.3133	2.589	-1.011
x=0.00 (3 T)	-0.3763	1.012	-1.478	-0.07327	0.7181	-0.2298
x=0.05 (0 T)	-19.46	48.02	-111.6	-3.747	56.81	-11.5
x=0.05 (3 T)	-9.097	20.86	-42.3	-1.695	21.06	-5.301

表3 La0.8Sr0.2Mn0.9Al0.1O3的小极化子模型(SPH)拟合参数

Table 3 Fitting parameters of small polaron hopping model for La0.8Sr0.2Mn0.9Al0.1O3

Al contents (magnetic field)	Temperature region/K	θ_D/K	υ_ph/(×10¹³, Hz)	ρ_α/(×10⁻⁵, Ω·m·K^-1)	E_a/meV	R²
x=0.10 (0 T)	[259.606, 300]	527.2478	1.10	0.374	102.73	0.99923
x=0.10 (3 T)	[277.554, 300]	563.2365	1.17	0.812	81.64	0.99623

表4 La0.8Sr0.2Mn1-xAlxO3 (0.15≤x≤0.25)的变程跳跃模型(VRH)拟合参数

Table 4 Fitting parameters of variable range hopping model for La0.8Sr0.2Mn1-xAlxO3 (0.15≤x≤0.25)

Al contents (Magnetic field)	Temperature region/K	R²	T₀/(×10⁶, K)	ρ₀/(×10^-6, Ω·m)	N(E)/( ×10¹⁴, nm^-3·meV^-1)	R_h(75 K)/nm	E_h(75 K)/meV
x=0.15 (0 T)	[225.64, 300]	0.9994	13.39103	0.03897	2.21487	0.41377	94.025
x=0.15 (3 T)	[259.65, 300]	0.9978	6.789	0.38214	4.36875	0.34914	79.34
x=0.20 (0 T)	[132.31, 300]	0.9993	3.75859	275.281	7.8911	0.535565	121.702
x=0.20 (3 T)	[155.4, 300]	0.99911	2.14391	4292.18	13.8343	0.465433	105.765
x=0.25 (0 T)	[50, 300]	0.99814	12.56367	0.01927	2.36073	0.724161	164.558
x=0.25 (3 T)	[50, 300]	0.99664	7.91716	0.35257	3.74622	0.645206	146.616

图4 La0.8Sr0.2Mn1-xAlxO3 (0.1≤x≤0.25)的磁电阻-温度曲线

Fig. 4 Magnetoresistance-temperature curves of La0.8Sr0.2Mn1-xAlxO3 (0.1≤x≤0.25)

参考文献 19

[1]	DHAHRI N, DHAHRI A, CHERIF K, et al. Effect of Co substitution on magnetocaloric effect in La_0.67Pb_0.33Mn_1-_xCo_xO₃ (0.15≤x≤0.3). Journal of Alloys and Compounds, 2010, 507(2): 405. DOI URL
[2]	AL-YAHMADI I, GISMELSEED A, AL MA’MARI F, et al. Structural, magnetic and magnetocaloric effect studies of Nd_0.6Sr_0.4A_xMn_1-_xO₃ (A=Co, Ni, Zn) perovskite manganites. Journal of Alloys and Compounds, 2021, 875: 159977. DOI URL
[3]	BALLY M, KHAN F. Structural, dielectric and magnetic properties of La_0.55Sr_0.45MnO₃ polycrystalline perovskite. Journal of Magnetism and Magnetic Materials, 2020, 509: 166897. DOI URL
[4]	HAGHIRI-GOSNET A, RENARD J. CMR manganites: physics, thin films and devices. Journal of Physics D: Applied Physics, 2003, 36(8): R127. DOI URL
[5]	THANH T D, PHAN T, THANH P Q, et al. Electrical and magnetotransport properties of La_0.7Ca_0.3Mn_1-_xCo_xO₃. IEEE Transactions on Magnetics, 2014, 50(6): 1.
[6]	LIU H, WANG C, WU L, et al. Effect of Ho-doping on structural, electrical and magnetic properties of La_0.7Sr_0.3MnO₃ ceramics prepared by plasma-activated sintering. Journal of Materials Science, 2018, 53(4): 2375. DOI URL
[7]	NGAN L, DANG N, PHUC N, et al. Magnetic and transport behaviors of Co substitution in La_0.7Sr_0.3MnO₃ perovskite. Journal of Alloys and Compounds, 2022, 911: 164967. DOI URL
[8]	CHU K L, LI H J, PU X R, et al. Influence of Ag doping on room-temperature TCR of La_0.67Sr_0.33-_xAg_xMnO₃ polycrystalline ceramics. Journal of Materials Science: Materials in Electronics, 2020, 31(15): 12389. DOI URL
[9]	DHAHRI A, DHAHRI J, HCINI S, et al. Influence of Al substitution on physical properties of Pr_0.67Sr_0.33Mn_1-_xAl_xO₃ manganites. Applied Physics A, 2015, 120(1): 247. DOI URL
[10]	ZAIDI N, ELABASSI M, SELMI M, et al. Structural characterization and magnetic interactions of La_0.7Sr_0.25Na_0.05Mn_1-_xAl_xO₃. Journal of Superconductivity and Novel Magnetism, 2020, 33(8): 2257. DOI URL
[11]	ZHAO S, YUE X, LIU X. Tuning room temperature T_pand MR of La_1-_y(Ca_y_-_xSr_x)MnO₃ polycrystalline ceramics by Sr doping. Ceramics International, 2017, 43(5): 4594. DOI URL
[12]	LI L, ZHANG H, LIU X, et al. Structure and electromagnetic properties of La_0.7Ca_0.3-_xK_xMnO₃ polycrystalline ceramics. Ceramics International, 2019, 45: 10558. DOI URL
[13]	RAMIREZ A. Colossal magnetoresistance. Journal of Physics: Condensed Matter, 1997, 9(39): 8171-8199. DOI URL
[14]	THANH T, NGUYEN L, MANH D, et al. Structural, magnetic and magnetotransport behavior of La_0.7Sr_xCa_0.3-_xMnO₃ compounds. Physica B: Condensed Matter, 2012, 407(1): 145. DOI URL
[15]	SCHIFFER P, RAMIREZ A, BAO W, et al. Low temperature magnetoresistance and the magnetic phase diagram of La_1-_xCa_xMnO₃. Physical Review Letters, 1995, 75(18): 3336. PMID
[16]	YUE X, ZHAN Y, LIU X, et al. Enhanced electrical properties of La_0.7(Ca_0.2Sr_0.1)MnO₃ polycrystalline composites with Ag addition. Journal of Low Temperature Physics, 2015, 180(5): 356. DOI URL
[17]	BANERJEE A, PAL S, ROZENBERG E, et al. Adiabatic and non-adiabatic small-polaron hopping conduction in La_1-_xPb_xMnO₃₊_δ (0≤x≤0.5)-type oxides above the metal-semiconductor transition. Journal of Physics: Condensed Matter, 2001, 13(42): 9489. DOI URL
[18]	YIN X, LIU X, YAN Y, et al. Preparation of La_0.67Ca_0.33MnO₃: Ag_x polycrystalline by Sol-Gel method. Journal of Sol-Gel Science and Technology, 2014, 70(3): 361-365. DOI URL
[19]	JUNG W H. Evaluation of Mott’s parameters for hopping conduction in La_0.67Ca_0.33MnO₃above T_C. Journal of Materials Science Letters, 1998, 17(15): 1317. DOI URL

Al³⁺掺杂对La_0.8Sr_0.2Mn_1-_xAl_xO₃电输运性能的影响

Effects of Al³⁺ Doping on the Structure and Electrical Transport Property of La_0.8Sr_0.2Mn_1-_xAl_xO₃

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