The structural and transport properties of manganites with and 0.2 prepared by solid state reaction route are studied. These compounds are found to be crystallized in orthorhombic structural form. A shift in the metal-semiconductor/insulator transition temperature ( ) towards room temperature (289？K) with the substitution of Nd by La, as the value of is varied in the sequence (0, 0.1, and 0.2), has been provided. The shift in the , from 239？K (for ) to near the room temperature 289？K (for ), is attributed to the fact that the average radius of site-A increases with the percentage of La. The maximum temperature coefficients of resistance (TCR) of ( and 0.2) are found to be higher compared to its parent compound which is almost independent of . The electrical resistivity of the experimental results is explored by various theoretical models below and above . An appropriate enlightenment for the observed behavior is discussed in detail. 1. Introduction In the past few decades, AMnO3-type manganites have been extensively studied because of their richness in physical properties which is due to the simultaneous presence of spin, lattice, and orbital degrees of freedom [1–3]. Significant attention has been paid by many researchers in order to explore their potential for spacious technological applications such as read heads, magnetic information storage, low- and high-field magnetic sensors, IR detectors, and numerous other spintronic applications [4–11]. The substituted manganites provide high temperature coefficient of resistance (TCR) in bulk as well as in thin films at room temperature. This will motivate us to explore them for infrared radiation detectors (i.e., IR detector) for night vision applications [12]. Among all perovskite manganites, NdMnO3 is an antiferromagnetic insulator, characterized by a superexchange coupling between Mn3+ sites. This coupling is facilitated by a single electron predominated by strong correlation effects. On the other hand, partial substitution of Nd3+ ions with divalent cations (Sr, Ca, and Ba) results in mixed valance states of Mn, that is, Mn3+/Mn4+ which is responsible for the ferromagnetic Zener double exchange mechanism [13]. The most prevalent experimental way of affecting the physical properties of the manganites is either substituting cations at the A- or B-sites or varying the oxygen content in the regular perovskite structure [20–22]. The size mismatch at A-site generates internal chemical pressure within the lattice. Due to this structural disorder effect, the local oxygen displacement occurs, ensuing into bond
References
[1]
J. M. D. Coey, M. Viret, and S. Von Molnár, “Mixed-valence manganites,” Advances in Physics, vol. 48, no. 2, pp. 167–293, 1999.
[2]
D. H. Manh, P. T. Phong, T. D. Thanh, L. V. Hong, and N. X. Phuc, “La0.7Ca0.3MnO3 perovskite synthesized by reactive milling method: the effect of particle size on the magnetic and electrical properties,” Journal of Alloys and Compounds, vol. 491, no. 1-2, pp. 8–12, 2010.
[3]
P. K. Siwach, H. K. Singh, and O. N. Srivastava, “Low field magnetotransport in manganites,” Journal of Physics Condensed Matter, vol. 20, no. 27, Article ID 273201, 2008.
[4]
M. M. Seikh, L. Sudheendra, and C. N. R. Rao, “Magnetic properties of La0.5-xLnxSr0.5MnO3 (Ln？=？Pr, Nd, Gd and Y),” Journal of Solid State Chemistry, vol. 177, no. 10, pp. 3633–3639, 2004.
[5]
R. Von Helmolt, J. Wecker, B. Holzapfel, L. Schultz, and K. Samwer, “Giant negative magnetoresistance in perovskitelike La2/3Ba1/3MnOx ferromagnetic films,” Physical Review Letters, vol. 71, no. 14, pp. 2331–2333, 1993.
[6]
S. Jin, T. H. Tiefel, M. McCormack, R. A. Fastnacht, R. Ramesh, and L. H. Chen, “Thousandfold change in resistivity in magnetoresistive La-Ca-Mn-O films,” Science, vol. 264, no. 5157, pp. 413–415, 1994.
[7]
A.-M. Haghiri-Gosnet and J.-P. Renard, “CMR manganites: physics, thin films and devices,” Journal of Physics D, vol. 36, no. 8, pp. R127–R150, 2003.
[8]
J. Heremans, “Solid state magnetic field sensors and applications,” Journal of Physics D, vol. 26, no. 8, pp. 1149–1168, 1993.
[9]
S. Jin, M. McCormack, T. H. Tiefel, and R. Ramesh, “Colossal magnetoresistance in La-Ca-Mn-O ferromagnetic thin films (invited),” Journal of Applied Physics, vol. 76, no. 10, pp. 6929–6933, 1994.
[10]
J. Mira, J. Rivas, L. E. Hueso, F. Rivadulla, M. A. López Quintela, and C. A. Ramos, “Strong reduction of lattice effects in mixed-valence manganites related to crystal symmetry,” Physical Review B, vol. 65, no. 2, Article ID 024418, 5 pages, 2002.
[11]
L. Hueso and N. Mathur, “Dreams of a hollow future,” Nature, vol. 427, no. 6972, pp. 301–304, 2004.
[12]
J.-H. Kim and A. M. Grishin, “Free-standing epitaxial La1-x(Sr,Ca)xMnO3 membrane on Si for uncooled infrared microbolometer,” Applied Physics Letters, vol. 87, no. 3, Article ID 033502, 3 pages, 2005.
[13]
C. Zener, “Interaction between the d-shells in the transition metals. II. Ferromagnetic compounds of manganese with Perovskite structure,” Physical Review, vol. 82, no. 3, pp. 403–405, 1951.
[14]
P. Schiffer, A. P. Ramirez, W. Bao, and S. W. Cheong, “Low temperature magnetoresistance and the magnetic phase diagram of La1-xCaxMnO3,” Physical Review Letters, vol. 75, no. 18, pp. 3336–3339, 1995.
[15]
E. S. Vlakhov, R. A. Chakalov, R. I. Chakalova et al., “Influence of the substrate on growth and magnetoresistance of La0.7Ca0.3MnOz thin films deposited by magnetron sputtering,” Journal of Applied Physics, vol. 83, no. 4, pp. 2152–2157, 1998.
[16]
A. Urushibara, Y. Moritomo, T. Arima, A. Asamitsu, G. Kido, and Y. Tokura, “Insulator-metal transition and giant magnetoresistance in La1-xSrxMnO3,” Physical Review B, vol. 51, no. 20, pp. 14103–14109, 1995.
[17]
K. Kubo and N. Ohata, “A quantum theory of double exchange. I,” Journal of the Physical Society of Japan, vol. 33, no. 1, pp. 21–31, 1972.
[18]
G. J. Snyder, R. Hiskes, S. DiCarolis, M. R. Beasley, and T. H. Geballe, “Intrinsic electrical transport and magnetic properties of La0.67Ca0.33MnO3 and La0.67Sr0.33MnO3 MOCVD thin films and bulk material,” Physical Review B, vol. 53, no. 21, pp. 14434–14444, 1996.
[19]
M. Jaime, P. Lin, M. B. Salamon, and P. D. Han, “Low-temperature electrical transport and double exchange in La0.67(Pb,Ca)0.33MnO3,” Physical Review B, vol. 58, no. 10, pp. R5901–R5904, 1998.
[20]
L. Sudheendra and C. N. R. Rao, “Electronic phase separation in the rare-earth manganates (La1-xLnx)0.7Ca0.3MnO3 (Ln？=？Nd, Gd and Y),” Journal of Physics Condensed Matter, vol. 15, no. 19, pp. 3029–3040, 2003.
[21]
S. Asthana, D. Bahadur, A. K. Nigam, and S. K. Malik, “Magneto-transport studies on (Pr1/3Sm2/3)2/3A1/3MnO3 (A？=？Ca, Sr and Ba) compounds,” Journal of Physics Condensed Matter, vol. 16, no. 29, pp. 5297–5307, 2004.
[22]
S. Asthana, D. Bahadur, A. K. Nigam, and S. K. Malik, “Lattice effect on the magnetic and magneto-transport properties of (La1/3Sm2/3)0.67Ba0.33-x SrxMnO3 ( , 0.1, 0.2 and 0.33) compounds,” Journal of Alloys and Compounds, vol. 450, no. 1-2, pp. 136–141, 2008.
[23]
G. J. Yong, R. M. Kolagani, S. Adhikari et al., “Heteroepitaxy of Nd0.67Sr0.33MnO3 on silicon for bolometric x-ray detector application,” Review of Scientific Instruments, vol. 81, no. 11, Article ID 113906, 6 pages, 2010.
[24]
S. Bhattacharya, R. K. Mukherjee, B. K. Chaudhuri, and H. D. Yang, “Effect of Li doping on the magnetotransport properties of La0.7Ca0.3-yLiyMnO3 system: decrease of metal-insulator transition temperature,” Applied Physics Letters, vol. 82, no. 23, pp. 4101–4103, 2003.
[25]
J. M. De Teresa, M. R. Ibarra, J. Blasco et al., “Spontaneous behavior and magnetic field and pressure effects on La2/3Ca1/3MnO3 perovskite,” Physical Review B, vol. 54, no. 2, pp. 1187–1193, 1996.
[26]
M. Dominguez, S. M. Bhagat, S. E. Lofland et al., “Giant magnetoresistance at microwave frequencies,” Europhysics Letters, vol. 32, no. 4, article 349, 1995.
[27]
A. Banerjee, S. Pal, and B. K. Chaudhuri, “Nature of small-polaron hopping conduction and the effect of Cr doping on the transport properties of rare-earth manganite La0.5Pb0.5Mn1-xCrxO3,” Journal of Chemical Physics, vol. 115, no. 3, pp. 1550–1558, 2001.
[28]
A. Urushibara, Y. Moritomo, T. Arima, A. Asamitsu, G. Kido, and Y. Tokura, “Insulator-metal transition and giant magnetoresistance in La1-xSrxMnO3,” Physical Review B, vol. 51, no. 20, pp. 14103–14109, 1995.
[29]
L. Pi, L. Zheng, and Y. Zhang, “Transport mechanism in polycrystalline La0.825Sr0.175Mn1-xCuxO3,” Physical Review B, vol. 61, no. 13, pp. 8917–8921, 2000.
[30]
S. Asthana, D. Joonghoe, and D. Bahadur, “Effects of A-site ionic size variation on the magnetic and transport properties of (PrxSm1-x)2/3Sr1/3MnO3 ( ),” Physica Status Solidi (B), vol. 244, no. 12, pp. 4542–4545, 2007.
[31]
V. Y. Zerov and V. G. Malyarov, “Heat-sensitive materials for uncooled microbolometer arrays,” Journal of Optical Technology, vol. 68, no. 12, pp. 939–948, 2001.
[32]
V. G. Malyarov, “Uncooled thermal IR arrays,” Journal of Optical Technology, vol. 69, no. 10, pp. 750–760, 2002.
[33]
S. Sedky, P. Fiorini, K. Baert, L. Hermans, and R. Mertens, “Characterization and optimization of infrared poly SiGe bolometers,” IEEE Transactions on Electron Devices, vol. 46, no. 4, pp. 675–682, 1999.
[34]
M. Almasri, Z. ？elik-Butler, D. P. Butler, A. Yaradanakul, and A. Yildiz, “Uncooled multimirror broad-band infrared microbolometers,” Journal of Microelectromechanical Systems, vol. 11, no. 5, pp. 528–535, 2002.
[35]
A. P. Gruzdeva, V. Y. Zerov, O. P. Konovalova et al., “Bolometric and noise properties of elements for uncooled IR arrays based on vanadium dioxide films,” Journal of Optical Technology, vol. 64, no. 12, pp. 1110–1113, 1997.
[36]
C. Chen, X. Yi, J. Zhang, and X. Zhao, “Linear uncooled microbolometer array based on VOx thin films,” Infrared Physics and Technology, vol. 42, no. 2, pp. 87–90, 2001.
[37]
V. Y. Zerov, V. G. Malyarov, I. A. Khrebtov, Y. V. Kulikov, I. I. Shaganov, and A. D. Smirnov, “Uncooled membrane-type linear microbolometer array based on a VOx film,” Journal of Optical Technology, vol. 68, no. 6, pp. 428–431, 2001.
[38]
G. F. Dionne, “Magnetic exchange and charge transfer in mixed-valence manganites and cuprates,” Journal of Applied Physics, vol. 79, no. 8, pp. 5172–5174, 1996.
[39]
N. F. Mott, “Conduction in glasses containing transition metal ions,” Journal of Non-Crystalline Solids, vol. 1, no. 1, pp. 1–17, 1968.
[40]
M. Viret, L. Ranno, and J. M. D. Coey, “Magnetic localization in mixed-valence manganites,” Physical Review B, vol. 55, no. 13, pp. 8067–8070, 1997.
[41]
W.-H. Jung, “Evaluation of Mott's parameters for hopping conduction in La0.67Ca0.33MnO3 above Tc,” Journal of Materials Science Letters, vol. 17, no. 15, pp. 1317–1319, 1998.
[42]
L. S. Ewe, I. Hamadneh, H. Salama, N. A. Hamid, S. A. Halim, and R. Abd-Shukor, “Magnetotransport properties of La0.67Ca0.33MnO3 with different grain sizes,” Applied Physics A, vol. 95, no. 2, pp. 457–463, 2009.
[43]
W. Zhang, I. W. Boyd, M. Elliott, and W. Herrenden-Harkerand, “Transport properties and giant magnetoresistance behavior in La-Nd-Sr-Mn-O films,” Applied Physics Letters, vol. 69, no. 8, pp. 1154–1156, 1996.
