RT Journal Article
T1 Interplay between double-exchange, superexchange, and Lifshitz localization in doped manganites
A1 Alonso, J. L.
A1 Fernández Pérez, Luis Antonio
A1 Guinea, F.
A1 Laliena, V.
A1 Martín Mayor, Víctor
AB Considering the disorder caused in manganites by the substitution Mn→Fe or Ga, we accomplish a systematic study of doped manganites begun in previous papers. To this end, a disordered model is formulated and solved using the variational mean-field technique. The subtle interplay between double exchange, superexchange, and disorder causes similar effects on the dependence of T_(C) on the percentage of Mn substitution in the cases considered. Yet, in La_(2/3)Ca_(1/3)Mn_(1-y)Ga_(y)O_(3) our results suggest a quantum critical point (QCP) for y ≈ 0.1–0.2, associated to the localization of the electronic states of the conduction band. In the case of La_(x)Ca_(x)Mn_(1-y)Fe_(y)O_(3) (with x = 1/3,3/8) no such QCP is expected.
PB American Physical Society
SN 1098-0121
YR 2002
FD 2002-09-01
LK https://hdl.handle.net/20.500.14352/60012
UL https://hdl.handle.net/20.500.14352/60012
LA eng
NO 1) S. Sachdev, Quantum Phase Transitions (Cambridge University Press, Cambridge, England, 1999)  -- ibid, Science, 288, 475 (2000)  -- ibid, Physica A, 313, 252 (2002).2)  J. Hertz, Phys. Rev. B, 14, 1165 (1976)  -- T. Moriya, Spin Fluctuations in Itinerant Electron Magnetism (Springer, Berlin, 1985)  -- A. J. Millis, Phys. Rev. B, 48, 7183 (1993).3) D. Belitz, T. R. Kirkpatrick, cond-mat/0106279 (unpublished), and references therein.4) K. Wilson, J. Kogut, Phys. Rep., 12, 75 (1974).5) S. Caprara, C. Castellani, C. Di Castro, M. Grilli, A. Perali, Physica B, 280, 196 (2000)  -- C. Di Castro, L. Benfatto, S. Caprara, C. Castellani, M. Grilli, Physica C, 341-348, 1715 (2000).6) E. Dagotto, T. M. Rice, Science, 271, 618 (1996).7) A. J. Millis, A. J. Schofield, G. G. Lonzarich, S. A. Grigera, Phys. Rev. Lett., 88, 217204 (2002).8) F. Iglói, R. Juhász, P. Lajko, et al., Phys. Rev. Lett., 86, 1343 (2001)  -- E. Carlon, P. Lajko, F. Iglói, ibid., 87, 277201 (2001).9) P. A. Lee, T. V. Ramakrishna, Rev. Mod. Phys., 57, 287 (1985).10) V. N. Smolyaninova, X. C. Xie, F. C. Zhang, M. Rajeswari, R. L. Greene, S. Das Sarma, Phys. Rev. B, 62, 3010 (2000).11) J. M. D. Coey, M. Viret, S. von Molnar, Adv. Phys., 48, 167 (1999).12) Y. Sun, X. Xu, L. Zheng, Y. Zhang, Phys. Rev. B, 60, 12 317 (1999).13) J. Blasco, J. García, J. M. de Teresa, M. R. Ibarra, J. Pérez, P. A. Algarabel, C. Marquina, Phys. Rev. B, 55, 8905 (1997).14) K. H. Ahn, X. S. Wu, C. L. Chien, Phys. Rev. B, 54, 15 299 (1996).15) J. R. Sun, G. H. Rao, B. G. Shen, H. K. Wong, Appl. Phys. Lett., 73, 2998 (1998).16) M. M. Xavier, Jr., F. A. O. Cabral, J. H. de Araújo, C. Chesman, T. Dumelow, Phys. Rev. B, 63, 012408 (2000).17) J. Mira, J. Rivas, F. Rivadulla, C. Vázquez-Vázquez, M. A. López-Quintela, Phys. Rev. B, 60, 2998 (1999).18) P. A. Algarabel, J. M. de Teresa, J. Blasco, M. R. Ibarra, talk at the Thematic Network Meeting on Colossal Magnetoresistance, Calella, Spain, February 2002 (unpublished).19) J. Burgy, M. Mayr, V. Martín-Mayor, A. Moreo, E. Dagotto, Phys. Rev. Lett., 87, 277202 (2001).20) J. A. Verges, V. Martín-Mayor, L. Brey, Phys. Rev. Lett., 88, 136401 (2002).21) J. L. Alonso, L. A. Fernández, F. Guinea, V. Laliena, V. Martín-Mayor, Phys. Rev. B, 63, 064416 (2001).22) J. L. Alonso, L. A. Fernández, F. Guinea, V. Laliena, V. Martín-Mayor, Phys. Rev. B, 63, 054411 (2001).23) J. L. Alonso, L. A. Fernández, F. Guinea, V. Laliena, V. Martín-Mayor, Nucl. Phys. B, 596, 587 (2001).24) J. L. Alonso, J. A. Capitán, L. A. Fernández, F. Guinea, V. Martín-Mayor, Phys. Rev. B, 64, 054408 (2001).25) C. Zener, Phys. Rev., 82, 403 (1951)  -- P. W. Anderson, H. Hasegawa, ibid., 100, 675 (1955)  -- P. G. de Gennes, ibid., 118, 141 (1960).26) D. P. Arovas, F. Guinea, Phys. Rev. B, 58, 9150 (1998)  -- M. Yu. Kagan, D. I. Khomskii, M. V. Mostovoy, Eur. Phys. J. B, 12, 217 (1999).27) Phonons are crucial to understand magnetoresistance effects, see Ref. 20 and references therein.28) A. Tzavellas, K. N. Trohidou, D. Kechrakos, N. Moutis, Appl. Phys. Lett., 77, 3627 (2000).29) See, e.g., G. Parisi, Field-Theory, Disorder and Simulations, Lecture Notes in Physics Vol. 49 (World Scientific, Singapore, 1992).30) A. Kaneko, T. Ohtsuki, Ann. Phys. (Leipzig), 8, 121 (1999).31) We obtain the DOS numerically, see Ref. 33 and C. Benoit, E. Royer, G. Poussigue, J. Phys.: Condens. Matter, 4, 3125 (1992)  -- P. Turchi, F. Ducastelle, G. Tréglia, J. Phys. C, 15, 2891 (1982).32) V. Martín-Mayor, G. Parisi, P. Verrocchio, Phys. Rev. E, 62, 2373 (2000).
NO © 2002 American Physical Society. We thank P. A. Algarabel, J. Blasco, J. García, R. Ibarra, J. M. de Teresa, and especially Domingo González, for discussions. The authors acknowledge financial support from CICyT (Spain) through Grant Nos. PB96-0875, AEN99- 0990, FPA2000-0956, and FPA2000-1252. V.M.-M. was supported by E.C. Contract No. HPMF-CT-2000-00450.
NO CICyT (Spain)
NO E.C.
DS Docta Complutense
RD 15 may 2024