Please use this identifier to cite or link to this item:
標題: The magnetic properties of La0.8Ba0.2MnO3 nanoparticles
作者: 鄭人瑞
Cheng, Jen-Jui
關鍵字: nanoparticles
magnetocaloric effect
出版社: 物理學系所
引用: [1] A.J. Rondinone, A.C.S. Samia, and Z.J. Zhang. Superparamagnetic relaxation and magnetic anisotropy energy distribution in CoFe2O4 spinel ferrite nanocrystallites. J. Phys. Chem. B, 103(33):6876-6880, 1999. [2] Young Sun, M. B. Salamon, K. Garnier, and R. S. Averback. Memory effects in an interacting magnetic nanoparticle system. Phys. Rev. Lett., 91(16):167206, Oct 2003. [3] C. Liu and Z.J. Zhang. Size-dependent superparamagnetic properties of Mn spinel ferrite nanoparticles synthesized from reverse micelles. Chem. Mater, 13(6):2092- 2096, 2001. [4] C.P. Bean and J.D. Livingston. Superparamagnetism. Journal of Applied Physics, 30:S120, 1959. [5] LE Hueso, P. Sande, DR Migu´ens, J. Rivas, F. Rivadulla, and M.A. L´opez- Quintela. Tuning of the magnetocaloric effect in La0.67Ca0.33MnO3−± nanoparticles synthesized by sol-gel techniques. Journal of Applied Physics, 91(12):9943-9947, 2002. [6] I. Yeung, R. M. Roshko, and G. Williams. Arrott-plot criterion for ferromagnetism in disordered systems. Phys. Rev. B, 34(5):3456-3457, Sep 1986. [7] Ammon Aharony and E. Pytte. Infinite susceptibility phase in random uniaxial anisotropy magnets. Phys. Rev. Lett., 45(19):1583-1586, Nov 1980. [8] T. Jonsson, P. Nordblad, and P. Svedlindh. Dynamic study of dipole-dipole interaction effects in a magnetic nanoparticle system. Physical Review B, 57(1):497-504, 1998. [9] CP Bean. Hysteresis loops of mixtures of ferromagnetic micropowders. Journal of Applied Physics, 26(11):1381-1383, 1955. [10] K. Binder and A.P. Young. Spin glasses: Experimental facts, theoretical concepts, and open questions. Reviews of Modern physics, 58(4):801-976, 1986. [11] P.G. Radaelli, M. Marezio, H.Y. Hwang, and S-W. Cheong. Structural Phase Diagram of Perovskite A0.7´A0.3MnO3(A= La, Pr; ´A= Ca, Sr, Ba): A New Imma Allotype. Journal of Solid State Chemistry, 122(2):444-447, 1996. [12] A.L. Patterson. The Scherrer formula for X-ray particle size determination. Physical review, 56(10):978-982, 1939. [13] S.K. Panda, A. Antonakos, E. Liarokapis, S. Bhattacharya, and S. Chaudhuri. Optical properties of nanocrystalline SnS2 thin films. Materials Research Bulletin, 42(3):576-583, 2007. [14] A.H. Lu, E.L. Salabas, and F. Sch¨uth. Magnetic nanoparticles: synthesis, protection, functionalization, and application. Angewandte Chemie International Edition, 46(8):1222-1244, 2007. [15] T. Brown, W. Li, X.Z. Zhou, H.P. Kunkel, G. Williams, Y. Mukovskii, and D. Shulyatev. Comparisons of the high-and low-field magnetic anisotropies in a single-crystal manganite and a polycrystalline cobaltite. EPL(Europhysics Letters), 72:809-815, 2005. [16] R.C. Budhani, C. Roy, L.H. Lewis, Q. Li, and A.R. Moodenbaugh. Magnetic ordering and granularity effects in La1-xBaxMnO3. Journal of Applied Physics, 87:2490, 2000. [17] M.A. L´opez-Quintela, L E Hueso, J. Rivas, and F. Rivadulla. Intergranular magnetoresistance in nanomanganites. Nanotechnology, 14:212-219, 2003. [18] N. Zhang, W. Ding, W. Zhong, D. Xing, and Y. Du. Tunnel-type giant magnetoresistance in the granular perovskite La0.85Sr0.15MnO3. Phys. Rev. B, 56:8138, 1997. [19] D. Predoi, V. Kuncser, E. Tronc, M. Nogues, U. Russo, G. Principi, and G. Filoti. Magnetic relaxation phenomena and inter-particle interactions in nanosized °- Fe2O3 systems. Journal of Physics: Condensed Matter, 15:1797, 2003. [20] X. Bohigas, J. Tejada, E. Del Barco, X.X. Zhang, and M. Sales. Tunable magnetocaloric effect in ceramic perovskites. Applied Physics Letters, 73:390, 1998. [21] R.D. McMichael, J.J. Ritter, and R.D. Shull. Enhanced magnetocaloric effect in Gd3Ga5-xFexO12. Journal of applied physics, 73(10):6946-6948, 1993. [22] R.D. McMichael, R.D. Shull, L.J. Swartzendruber, and R.E. Bennett. Magnetocaloric effect in superparamagnets. Journal of Magnetism and Magnetic Materials, 111(1-2):29-33, 1992. [23] R.D. Shull. Magnetocaloric effect of ferromagnetic particles. Journal of Applied Physics, 29:2614-2615, 1993. [24] L.H. Bennett, R.D. McMichael, L.J. Swartzendruber, R.D. Shull, and R.E. Watson. Monte Carlo and mean-field calculations of the magnetocaloric effect of ferromagnetically interacting clusters. Journal of Magnetism and Magnetic Materials, 104-117:1904-1905, 1992. [25] Weili Luo, Sidney R. Nagel, T. F. Rosenbaum, and R. E. Rosensweig. Dipole interactions with random anisotropy in a frozen ferrofluid. Phys. Rev. Lett., 67(19):2721-2724, Nov 1991. [26] T. Jonsson, J. Mattsson, C. Djurberg, F. A. Khan, P. Nordblad, and P. Svedlindh. Aging in a magnetic particle system. Phys. Rev. Lett., 75(22):4138-4141, Nov 1995. [27] K. Jonason and P. Nordblad. Overlap length scale of a re-entrant ferromagnet. Journal of Magnetism and Magnetic Materials, 177:95-96, 1998. [28] RS Freitas, L. Ghivelder, F. Damay, F. Dias, and LF Cohen. Magnetic relaxation phenomena and cluster glass properties of La0.7-xYxCa0.3MnO3 manganites. Physical Review B, 64(14):144404, 2001. [29] Y. Tang, Y. Sun, and Z. Cheng. Magnetic aging above the freezing temperature in La0.82Sr0.18CoO3. Journal of Physics: Condensed Matter, 20:095208, 2008. [30] DNH Nam, R. Mathieu, P. Nordblad, NV Khiem, and NX Phuc. Ferromagnetism and frustration in Nd0.7Sr0.3MnO3. Physical Review B, 62(2):1027-1032, 2000. [31] D.S. Fisher and D.A. Huse. Nonequilibrium dynamics of spin glasses. Physical Review B, 38(1):373-385, 1988. [32] F. Lefloch, J. Hammann, M. Ocio, and E. Vincent. Can aging phenomena discriminate between the droplet model and a hierarchical description in spin glasses? EPL (Europhysics Letters), 18:647, 1992. [33] E. Vincent, JP Bouchaud, J. Hammann, and F. Lefloch. Contrasting effects of field and temperature variations on ageing in spin glasses. Philosophical Magazine Part B, 71(4):489-500, 1995.
摘要: 強關聯電子系統(strongly correlated electron system)不僅在高溫超導領域有著驚人的現象,並與傳統超導體有不同的凝態物理理論架構。在磁性現象方面,過渡金屬氧化物LaMnO3經過摻雜陽離子後,金屬絕緣相變及龐磁阻(colossal magnetoresistance)等效應產生,其電子間的強關聯性所衍生豐富的物理特性,一直是凝態物理研究的重點之一。為了更了解龐磁阻化合物,我們運用脈衝式雷射沉積技術(Pulsed Laser Deposition),成功製造出La0.8Ba0.2MnO3奈米微粒,並藉由X光繞射分析儀(X-ray diffractometer),場發射掃描式電子顯微鏡(FE-SEM),場發射穿透式電子顯微鏡(FE-TEM),對於奈米微粒做成分分析及粒徑分佈觀測。運用超導量子干涉儀量測奈米微粒的磁性,得到相轉變溫度發生在室溫。並測量計算樣品在低於磁性轉變溫度時的磁熱效應變化,運用Arrott-polt準則觀察出微粒系統的隨機各向異性,而在低溫時呈現自旋玻璃態的行為。再藉由磁鬆弛實驗,來討論La0.8Ba0.2MnO3奈米微粒在不同溫度下的動態交互作用。
The mixed valence manganites bulk material La0.8Ba0.2MnO3 has been discovered colossal magnetoresistance. In order to understand the mechanism of strongly correlated electrons system on the prototypical CMR compound, the size effect on the magnetism was studied over wide temperature and magnetic field ranges. Nanoparticles of La0.8Ba0.2MnO3 were fabricated by Pulsed Laser Deposition technique. The phase and size of the nanoparticles were examined by the X-ray diffraction, FE-SEM and HR-TEM. According to the experimental results on the nanoparticles, some of the most important magnetic and transport properties of mixed-valence manganite were presented. The Arrott plot and magnetocaloric effect show clear features of random anisotropy in nanoparticles at superparamagnetic state. We carried out a detailed study on the relaxation and aging behavior at various temperatures, it was found that the magnetization as a function of time can be described well by a stretched exponential equations, which manifests spin glass dynamics at low temperature. Furthermore, we have performed the affect of the temperature and applied field change on the ZFC magnetic relaxation, the memory phenomenon in the dc magnetization of La0.8Ba0.2MnO3 nanoparticles were observed.
其他識別: U0005-2508201017391200
Appears in Collections:物理學系所



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.