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Saulius Kaciulis Eleonora Bolli Alessio Mezzi Milita Vagner Valentina Plausinaitiene Skirmantas Kersulis Nerija Zurauskiene Rasuole Lukose 《Surface and interface analysis : SIA》2020,52(12):900-906
In the present study were studied the ferromagnetic La1−xSrx (Mn1−yCoy)zO3 (LSMCO) films with Co content y = 0 to 0.18, grown on LaAlO3 substrates by advantageous pulsed-injection metalorganic chemical vapor deposition technique. The LSMCO films exhibit negative colossal magnetoresistance effect; therefore, they are interesting as potential material for the applications in magnetic field sensing. The changes of lattice volume in the investigated LSMCO films were monitored by X-ray diffraction measurements revealing a transition from tensile to compressive strain with increase of Co content. Additionally, from the atomic force microscopy images, the surface smoothening with increase of y was determined. Despite the reduction of the out-of-plane lattice parameter of LSMCO, the increase of lattice volume in the whole Co-doping range was observed. The X-ray photoelectron spectroscopy combined with Ar+ ion sputtering was used for the investigation of chemical composition of the LSMCO films and demonstrated the change and redistribution of oxidation states of Mn and Co on the surface and in the volume of the films. Regardless of the structural changes and charge distribution of Co and Mn cations, epitaxial LSMCO exhibits ferromagnetic properties and magnetoresistance values increases with augmenting Co content in the range of y = 0 to 0.18. 相似文献
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Zhiming Wang Qingyu XuJingzhi Sun Jian PanHe Zhang 《Physica B: Condensed Matter》2011,406(8):1436-1440
Room temperature magnetocaloric effect in La-deficient bulk perovskite manganite La0.7MnO3−δ prepared by conventional solid-state reaction has been reported. The maximum value of the magnetic entropy change (about−1.32 J/kg K) and the refrigerant capacity (approximately close to 37 J/kg) had been obtained at 290 K corresponding to a magnetic field variation of 1 T for La0.7MnO3−δ. It is the strong Jahn-Teller coupling that changes Mn-O bond length and Mn-O-Mn bond angles and then the canted spin arrangement and induces the strong double-exchange coupling to a comparatively high magnetic transition temperature. This Curie temperature near room temperature with easy fabrication and higher chemical stability makes La0.7MnO3−δ a potential candidate as a working substance in magnetic refrigeration technology. 相似文献
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Gongqi Yu Bin XuJinming Xiong Xiangfei LiuLi Liu Songliu Yuan 《Journal of magnetism and magnetic materials》2011,323(15):1925-1928
The effect of Cr doping on magnetic and electrical properties in the bilayer manganites La1.4Sr1.6(Mn1−yCry)2O7 (y=0-0.1) has been investigated. When y≤0.025, Cr doping enhances the three-dimensional magnetic transition temperature TC and the insulator-metal transition temperature TIM as well as decreases the peak resistivity at TIM, and the saturated magnetization decreases slightly. When y≥0.035, TIM decreases gradually accompanied by the increase of peak resistivity, but TC remains nearly constant, and the saturated magnetization decreases heavily. In the whole doping region, the two-dimensional magnetic transition temperature T? monotonously decreases with an increasing of Cr doping level. These results can be explained by considering different magnetic (including ferromagnetic and antiferromagnetic) interactions between Mn ions and Cr ions. 相似文献
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Weibin Liu Yingtang Zhang Wen Guan William Kinsman Xinqiang Yuan Ziyu Chen 《Physica B: Condensed Matter》2012,407(17):3405-3407
The magnetic properties of the perovskite form of LaMnO3 have been shown strong interest in recent years due to its high potential for use in magnetic devices. In this paper, the magnetic properties of a 30% terbium-doped LaMnO3 (LMTO) perovskite manganite synthesized by a conventional solid-state reaction were investigated. Data on these properties was recorded periodically via SQUID and VSM to reveal it to be best described magnetically as a spin glass system. Thus, the time effect must be taken into consideration in instantaneously determining this material’s spin glass state as well as the overall magnetic properties in the absence of a magnetic field. The results of this paper point to a more in-depth understanding of the change in magnetic properties associated with doped LaMnO3. 相似文献
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S. Sankarrajan S. Aravindan R. Yuvakkumar K. Sakthipandi V. Rajendran 《Journal of magnetism and magnetic materials》2009,321(21):3611-3620
Nd1−xSrxMnO3 perovskite manganite material with different compositions (x=0.31, 0.35, 0.37, 0.39 and 0.41) have been prepared employing solid-state reaction technique. The ultrasonic velocities and attenuation of the above samples have been measured employing through transmission method operated at a fundamental frequency of 5 MHz over wide range of temperatures. The temperature dependence of ultrasonic velocities, attenuation, relative percentage variation in velocities and elastic constants show an interesting anomaly in all compositions. The observed anomalies in ultrasonic parameters at Tc in all compositions have been revealed in terms of existence of ferromagnetic (FM) state. Similarly, the anomalies at Tco show the transition from FM to charge-ordered antiferromagnetic (AFM) state. The observed results have been used to explore the competitions between FM and AFM. 相似文献
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The effects of Nd-doping on the transport and magnetic properties of La2/3−yNdySr1/3MnO3 (y=0, 1/3, 2/3) are studied theoretically by using the generalized-gradient-corrected full-potential method. In order to investigate the coupling between Nd and Mn, the electronic structures of La2/3−yNdySr1/3MnO3 with ferromagnetic (FM) and antiferromagnetic (AFM) arrangements of Nd and Mn sublattices are calculated. The calculation for FM La2/3−yNdySr1/3MnO3 yields a half-metallic band structure, while the ferrimagnetic (FiM) system is found to have a metallic character. Hybridization of Nd 4f, Mn 3d, and O 2p bands around Fermi level (EF) is observed, suggesting the coupling between Nd and Mn is mediated by O 2p carriers. The qualitative features of transport and magnetic properties of such a two-spin system can be interpreted in terms of half-metallic FM domains being mixed up with metallic FiM domains. The proportion of FM domains varying with Nd-doping concentration has strong influences on the magnetoresistance. 相似文献
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A.I. Shames E. Rozenberg Ya.M. Mukovskii E. Sominski A. Gedanken 《Journal of magnetism and magnetic materials》2008,320(14):e8-e11
Electron magnetic resonance (EMR) was studied on crystalline bulk and nanometer-sized samples of the same La0.7Ca0.3MnO3 manganite compound aiming to compare their magnetic homogeneities. The results obtained show that single-crystalline bulk sample is less homogeneous than the nanocrystalline one. Except for higher homogeneity, the nanometer-sized sample also demonstrates a weaker magnetic anisotropy. As a result, well-pronounced coexistence of different magnetic phases (coexistence of ferromagnetic and paramagnetic resonance signals) is observed in the bulk sample, while it is absent in the nanocrystalline one. It is suggested that such strong difference is directly connected to the difference in structural state of the samples. 相似文献
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