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Author (up) Betancourth, D.; Correa, V. F.; Facio, J.I.; Fernández J.; Vildosola, V.; Lora-Serrano, R.; Cadogan, J.M.; Aligia, A.A.; Cornaglia, P.S.; García D.J. doi  openurl
  Title Magnetostriction reveals orthorhombic distortion in tetragonal Gd compounds Type Journal Article
  Year 2019 Publication Physical Review B Abbreviated Journal Phys. Rev. B  
  Volume 99 Issue Pages 134406  
  Keywords  
  Abstract We report detailed thermal expansion and magnetostriction experiments on GdCoIn5 and GdRh(In1−xCdx )5

(x = 0 and 0.025) single-crystal samples that show a sudden change in the dilation at a field B for temperatures

below the Néel transition temperature TN . We present a first-principles model including crystal-field effects,

dipolar and exchange interactions, and the dependence of the latter with lattice distortions in order to fully

account for the magnetostriction and magnetic susceptibility data. The mean-field solution of the model shows

that a transition between metastable states occurs at the field B. It also indicates that two degenerate phases

should coexist at temperatures below TN , which may explain the lack of observation, in high-resolution

x-ray experiments, of an orthorhombic distortion at the Néel transition, even though the experimentally

determined magnetic structure breaks the tetragonal symmetry and the magnetoelastic coupling from our model

is significant. These conclusions could be extended to other tetragonal Gd-based compounds that present the

same phenomenology.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ victor.correa @ Serial 815  
Permanent link to this record
 

 
Author (up) Betancourth, D.; Correa, V.F.; García, D.J. doi  openurl
  Title Evidence of a Low Energy Anisotropy in GdCoIn_5 Type Journal Article
  Year 2015 Publication Journal of Low Temperature Physics Abbreviated Journal J. Low Temp. Phys.  
  Volume 179 Issue 1-2 Pages 90-93  
  Keywords Rare earth magnetism; Antiferromagnetic transition; Anisotropy  
  Abstract We investigate the effects of an applied magnetic field on the magnetic properties of the antiferromagnet GdCoIn 5 . The prominent anisotropy observed in the susceptibility below TN is rapidly suppressed by a field of just a few Tesla. Further evidence of this low energy-scale is obtained from magnetoresistance and magnetostriction experiments. The lattice length, particularly, shows a sudden change below 2 T when the magnetic field is applied perpendicular to the crystallographic c^ -axis.  
  Address  
  Corporate Author Thesis  
  Publisher Springer US Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-2291 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 710  
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Author (up) Betancourth, D.; Facio, J.I.; Pedrazzini, P.; Jesus, C.B.R.; Pagliuso, P.G.; Vildosola, V.; Cornaglia, P.S.; García, D. J.; Correa, V. F. url  doi
openurl 
  Title Low Temperature magnetic properties of GdCoIn5 Type Journal Article
  Year 2015 Publication Journal of Magnetism and Magnetic Materials Abbreviated Journal J. Magn. Magn. Mater.  
  Volume 374 Issue Pages 744-747  
  Keywords  
  Abstract A comprehensive experimental and theoretical study of the low temperature properties of GdCoIn5 was performed. Specific heat, thermal expansion, magnetization and electrical resistivity were measured in good quality single crystals down to 4He temperatures. All the experiments show a second-order-like phase transition at 30 K probably associated with the onset of antiferromagnetic order. The magnetic susceptibility shows a pronounced anisotropy below T N with an easy magnetic axis perpendicular to the crystallographic ĉ-axis. Total energy GGA+U calculations indicate a ground state with magnetic moments localized at the Gd ions and allowed a determination of the Gd-Gd magnetic interactions. Band structure calculations of the electron and phonon contributions to the specific heat together with Quantum Monte Carlo calculations of the magnetic contributions show a very good agreement with the experimental data. Comparison between experiment and calculations suggests a significant anharmonic contribution to the specific heat at high temperature (View the MathML sourceT≳100K).  
  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 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ victor.correa @ Serial 701  
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Author (up) Correa, V. F; Villagrán Asiares, A. G.; Betancourth, D.; Encina, S.; Pedrazzini, P.; Cornaglia, P.S.; García D.J.; Sereni, J. G.; Maiorov, B; Caroca-Canales, N; Geibel, Ch. doi  openurl
  Title Strong magnetoelastic effect in CeCo1−xFexSi as Néel order is suppressed Type Journal Article
  Year 2019 Publication Physical Review B Abbreviated Journal Phys. Rev. B  
  Volume 100 Issue Pages 184409  
  Keywords  
  Abstract A very strong magnetoelastic effect in the CeCo1−xFexSi alloys is reported. The strength of the magnetostrictive

effect can be tuned upon changing x. The moderate low-temperature linear magnetostriction observed at low

Fe concentrations becomes very large (L

L (16T, 2K) = 3 × 10−3) around the critical concentration xc ≈ 0.23 at

which the long-range antiferromagnetic order vanishes. Upon increasing doping through the nonmagnetic region

(x > xc), the magnetostriction strength gradually weakens again. The interplay between magnetic order and the

Kondo screening appears to cause an enhanced valence susceptibility slightly changing the Ce ions valence,

ultimately triggering the large magnetostriction observed around the critical concentration. Previous studies

of the evolution of the lattice parameters with x as well as magnetization and x-ray absorption spectroscopy

measurements support this hypothesis.
 
  Address  
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  Language Summary Language Original Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ victor.correa @ Serial 842  
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Author (up) Correa, V.F.; Betancourth, D.; Sereni, J.G.; Caroca-Canales, N.; Geibel, C. url  doi
openurl 
  Title Remarkable magnetostructural coupling around the magnetic transition in CeCo0.85Fe0.15Si Type Journal Article
  Year 2016 Publication Journal of Physics: Condensed Matter Abbreviated Journal J. Phys.: Condens. Matter  
  Volume 28 Issue 34 Pages 346003  
  Keywords magnetostriction, cerium compounds, magnetism  
  Abstract We report a detailed study of the magnetic properties of CeCo0.85Fe0.15Si under high magnetic

fields (up to 16 Tesla) measuring different physical properties such as specific heat, magnetization,

electrical resistivity, thermal expansion and magnetostriction. CeCo0.85Fe0.15Si becomes

antiferromagnetic at TN 6.7 K. However, a broad tail (onset at TX 13 K) in the specific heat

precedes that second order transition. This tail is also observed in the temperature derivative of

the resistivity. However, it is particularly noticeable in the thermal expansion coefficient where it

takes the form of a large bump centered at TX. A high magnetic field practically washes out that tail

in the resistivity. But surprisingly, the bump in the thermal expansion coefficient becomes a well

pronounced peak fully split from the magnetic transition at TN. Concurrently, the magnetoresistance

also switches from negative to positive above TN. The magnetostriction is considerable and

irreversible at low temperature ( (16T)4×10− L

L

4 at 2 K) when the magnetic interactions

dominate. A broad jump in the field dependence of the magnetostriction observed at low T may be

the signature of a weak ongoing metamagnetic transition. Taking altogether the results indicate the

importance of the lattice effects on the development of the magnetic order in these alloys.
 
  Address  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ victor.correa @ Serial 732  
Permanent link to this record
 

 
Author (up) Facio, J.I.; Betancourth, D.; Cejas Bolecek, N.R.; Jorge, G.A.; Pedrazzini, P.; Correa, V.F.; Cornaglia, P.S.; Vildosola, V.; García D.J. url  doi
openurl 
  Title Lattice specific heat for the RMIn5 (R=Gd, La,Y; M=Co, Rh) compounds: Non-magnetic contribution subtraction Type Journal Article
  Year 2016 Publication Journal of Magnetism and Magnetic Materials Abbreviated Journal J. Magn. Magn. Mater.  
  Volume 407 Issue Pages 406-4011  
  Keywords  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ victor.correa @ Serial 730  
Permanent link to this record
 

 
Author (up) Facio, J.I.; Betancourth, D.; Pedrazzini, P.; Correa, V. F; Vildosola, V.; García, D. J.; Cornaglia, P.S. url  doi
openurl 
  Title Why the Co-based 115 compounds are different: The case study of GdMIn5 (M = Co,Rh,Ir) Type Journal Article
  Year 2015 Publication Physical Review B Abbreviated Journal Phys. Rev. B  
  Volume 91 Issue Pages 014409  
  Keywords  
  Abstract The discovery in 2001 of superconductivity in some heavy fermion compounds of the RMIn5 (R = 4f or

5f elements; M = Co, Rh, Ir) family, has triggered an enormous amount of research into understanding the

physical origin of superconductivity and its relation with magnetism. Although many properties have been

clarified, there are still crucial questions that remain unanswered. One of these questions is the particular role

of the transition metal in determining the value of critical superconducting temperature (TC). In this work, we

analyze an interesting regularity that is experimentally observed in this family of compounds, where the lowest

N´eel temperatures are obtained in the Co-based materials. We focus our analysis on the GdMIn5 compounds

and perform density-functional-theory-based total-energy calculations to obtain the parameters for the exchange

coupling interactions between the magnetic moments located at the Gd3+ ions. Our calculations indicate that

the ground state of the three compounds is a C-type antiferromagnet determined by the competition between

the first- and second-neighbor exchange couplings inside GdIn3 planes and stabilized by the couplings across

MIn2 planes. We then solve a model with these magnetic interactions using a mean-field approximation and

quantum Monte Carlo simulations. The results obtained for the calculated N´eel and Curie-Weiss temperatures,

the specific heat, and the magnetic susceptibility are in very good agreement with the existent experimental data.

Remarkably, we show that the first-neighbor interplane exchange coupling in the Co-based material is much

smaller than in the Rh and Ir analogs which leads to a more two-dimensional magnetic behavior in the former.

This result explains the observed lower N´eel temperature in Co-115 systems and may shed light on the fact that

the Co-based 115 superconductors present the highest TC.
 
  Address  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ victor.correa @ Serial 705  
Permanent link to this record
 

 
Author (up) Sereni, J.G.; Gomez Berisso, M.; Betancourth, D.; Correa, V.F.; Canales, N.C.; Geibel, C. url  doi
openurl 
  Title Evidence for a dimensionality crossover at the disappearance of magnetism in the Kondo lattice alloy CeCo1-xFexSi Type Journal Article
  Year 2014 Publication Physical Review B Abbreviated Journal Phys. Rev. B  
  Volume 89 Issue 3 Pages 035107  
  Keywords  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ berisso @ 10.1103/PhysRevB.89.035107 Serial 677  
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