toggle visibility Search & Display Options

Select All    Deselect All
 |   | 
Details
   print
  Records Links
Author (up) Franco, D.G.; Carbonio, R.E.; Nieva, G. doi  openurl
  Title Change in the Magnetic Domain Alignment Process at the Onset of a Frustrated Magnetic State in Ferrimagnetic La2Ni(Ni1/3Sb2/3)O6 Double Perovskite Type Journal Article
  Year 2013 Publication IEEE Transactions on Magnetics Abbreviated Journal IEEE Trans. Magn.  
  Volume 49 Issue 8 Pages 4656-4659  
  Keywords coercive force; exchange interactions (electron); ferrimagnetic materials; frustration; magnetic domain walls; magnetic hysteresis; magnetic transitions; LaNi(Ni0.33Sb0.67)O6; applied magnetic field; coercive field; domain wall pinning; ferrimagnetic double perovskite; ferrimagnetic order transition; frustrated magnetic state; hysteresis data; low temperature regime; magnetic domain alignment process; magnetic exchange interactions; magnetization hysteresis loops; temperature dependence; Magnetic domain walls; Magnetic domains; Magnetic hysteresis; Magnetization; Nickel; Temperature distribution; Temperature measurement; Ferrimagnetic materials; magnetic analysis; magnetic domain walls; magnetic hysteresis  
  Abstract We have performed a combined study of magnetization hysteresis loops and time dependence of the magnetization in a broad temperature range for the ferrimagnetic La2Ni(Ni1/3Sb2/3)O6 double perovskite. This material has a ferrimagnetic order transition at ~100 K and at lower temperatures (~20 K) shows the signature of a frustrated state due to the presence of two competing magnetic exchange interactions. The temperature dependence of the coercive field shows an important upturn below the point where the frustrated state sets in. The use of hysteresis data, magnetization versus applied magnetic field, together with the magnetization versus time data provides a unique opportunity to distinguish between different scenarios for the low temperature regime. From our analysis, a strong domain wall pinning results in the best scenario for the low temperature regime. For temperatures larger than 20 K, the adequate scenario seems to correspond to a weak domain wall pinning.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0018-9464 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 668  
Permanent link to this record
 

 
Author (up) Franco, D.G.; Carbonio, R.E.; Nieva, G. doi  openurl
  Title Magnetic Properties of the Double Perovskites LaPbMSbO6 (M = Mn, Co, and Ni) Type Journal Article
  Year 2013 Publication IEEE Transactions on Magnetics Abbreviated Journal IEEE Trans. Magn.  
  Volume 49 Issue 8 Pages 4594-4597  
  Keywords X-ray diffraction; cobalt compounds; lanthanum compounds; lead compounds; magnetisation; manganese compounds; nickel compounds; paramagnetic-antiferromagnetic transitions; space groups; superexchange interactions; LaPbCoSbO6; LaPbMnSbO6; LaPbNiSbO6; M2+ distribution; Rietveld analysis; Sb5+ distribution; X-ray powder diffraction pattern; antiferromagnetic coupling; antiferromagnetic transition; aqueous synthetic route; disorder; double perovskites; ferrimagnetic characteristics; interaction paths; magnetic ions; magnetic properties; monoclinic crystals; octahedral sites; polycrystals; space group P2 1/n; super-superexchange paths; Ions; Magnetic properties; Magnetization; Manganese; Nickel; Temperature measurement; X-ray diffraction; Antiferromagnetic materials; transition metal compounds  
  Abstract New double perovskites LaPbMSbO6, where M2+ = Mn2+, Co2+, and Ni2+, were synthesized as polycrystals by an aqueous synthetic route at temperatures below 1000 °C. All samples are monoclinic, space group P21/n, as it is observed from Rietveld analysis of X-ray powder diffraction patterns. The distribution of M2+ and Sb5+ among the two octahedral sites have 3% of disorder for M2+ = Ni2+, whereas for M2+ = Mn2+ and Co2+ less disorder is found. The three samples have an antiferromagnetic transition, due to the antiferromagnetic coupling between M2 + through super-superexchange paths M2+-O2--Sb5+-O2--M2+. Transition temperatures are low: 8, 10 and 17 K for Mn2+, Co2+, and Ni2 + respectively, as a consequence of the relatively long distances between the magnetic ions M2+. Besides, for LaPbMnSbO6 a small transition at 45 K was found, with ferrimagnetic characteristics, possibly as a consequence of a small disorder between Mn2+ and Sb5+. This disorder would give additional and shorter interaction paths: superexchange Mn2+-O2--Mn2+.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0018-9464 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 669  
Permanent link to this record
 

 
Author (up) Gomez, M.E.; Campillo, G.; Ramirez, J.G.; Prieto, P.; Hoffmann, A.; Guimpel, J.; Haberkorn, N.; Condo, A.; Lovey, F. openurl 
  Title Magnetotransport properties in epitaxial exchange-biased La2/3Ca1/3MnO3/La1/3Ca2/3MnO3 superlattices Type Journal Article
  Year 2006 Publication IEEE Transactions on Magnetics Abbreviated Journal IEEE Trans. Magn.  
  Volume 42 Issue 10 Pages 2981-2983  
  Keywords  
  Abstract Superlattices of ferromagnetic (F) and antiferromagnetic (AF) oxide materials have attracted increased attention given the exchange bias or exchange anistropy phenomenon. Research on magnetic oxide superlattices has focused toward the technological goals of increasing magnetores stance in lower applied magnetic fields and more useful temperature ranges for various applications. Superlattices of F-LCMO and AF-LCMO layers were grown on (001)-oriented SrTiO3 substrates. We studied the temperature dependence of magnetotransport properties for a series of [AF-LCMO (7.6 nm)/F-LCMO (t(F))](N) superlattices as a function of the ferromagnetically doped layer thickness, t(F), while the antiferromagnetic (AF) layer thickness, t(AF), was kept constant. Magnetotransport measurements at different temperatures were done on a series of [AF(7.6 nm)IF(t(F))](N) superlattices. The ZFC resistance has a maximum at negative fields, for all multilayers, with descending fields (from 1 to -1 kOe). In all samples a shift along the field axis of the FC loop with respect to that of the ZFC loop is observed. The H-ex values determined from these displacements of the FC loops of the magnetoresistance loops increase when temperature decreases and its magnitude also depends on the ferromagnetic layer thickness.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0018-9464 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000240888700241 Approved no  
  Call Number BT @ hernan @ Serial 153  
Permanent link to this record
 

 
Author (up) Sereni, J.G.; Schmerber, G.; Kappler, J.P. doi  openurl
  Title Thermodynamic Behavior of Ce Compounds Close to a T->0 Critical Point Type Journal Article
  Year 2013 Publication IEEE Transactions on Magnetics Abbreviated Journal IEEE Trans. Magn.  
  Volume 49 Issue 8 Pages 4647-4651  
  Keywords cerium compounds; critical points; entropy; palladium compounds; specific heat; CePd3Bx; CePd3Bex; cerium compounds; critical point; entropy; specific heat; thermodynamic behavior; Compounds; Entropy; Heating; Saturation magnetization; Temperature dependence; Temperature measurement; Thermodynamics; Cerium; magnetic properties; thermodynamics  
  Abstract There is a reduced group of Ce very heavy Fermions (VHF) which do not order magnetically down to at least T ≈ 500 mK because they are very close to a Tord = 0 critical point. These compounds are at the top of the limT→ 0 Cm/T specific heat values because they collect very high density of low energy excitations. From the analysis of Cm(T)/T and entropy Sm(T) dependencies performed on selected CePd3Mx ternaries (where M = B and Be) a quantitative evaluation of an upper limit for the density of excitations can be proposed. These observations exclude any evidence of Cm(T)/T divergency as T→ 0 in agreement with thermodynamic laws. A comparison with selected Yb-base VHF supports these features.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0018-9464 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 664  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print

Save Citations:
Export Records: