### Cite Details

T. A. Ho, T. D. Thanh, Y. Yu, D. M. Tartakovsky, T. O. Ho, P. D. Thang, A.-T. Le, T.-L. Phan and S. C. Yu, "Critical behavior and magnetocaloric effect of Pr

_{1-x}Ca

_{x}MnO

_{3}",

* J. Appl. Phys.*, vol. 117, no. 17, doi:

10.1063/1.4914537, pp. 17D122, 2015

### Abstract

The critical behavior of Pr_{1−x}Ca_{x}MnO_{3} samples with *x =
0.25*, *0.27*, and *0.29* has been investigated. Detailed analyses of
magnetic-field dependences of magnetization at temperatures
around the paramagnetic-ferromagnetic transition, *M(H,T)*, reveal
that the samples undergo a second-order magnetic phase
transition. The Arrott plot method predicts the values of
critical parameters to be *T*_{C} ≈ 118 K, *β = 0.351 ± 0.003*,
*γ = 1.372 ± 0.002*, and *δ = 4.90 ± 0.02* for *x* = 0.25;
*T*_{C} ≈ 116 K, *β = 0.362 ± 0.002*, *γ = 1.132 ± 0.004*, and *δ
= 4.09 ± 0.03* for *x = 0.27*; and *T*_{C} ≈ 110 K, *β = 0.521 ±
0.002*, *γ = 0.912 ± 0.005*, and *δ = 2.71 ± 0.02* for *x =
0.29*. The values of *β = 0.351* (for *x = 0.25*) and *β = 0.362* (for *x = 0.27*) are close to the value *β
= 0.365* expected for the 3D Heisenberg model, proving an
existence of short-range ferromagnetic interactions in these
samples. A slight increase in Ca-doping content (*x = 0.29*) leads
to the shift of the *β* value (*= 0.521*) towards that of the
mean-field theory (with *β = 0.5*) characteristic of long-range
ferromagnetic interactions. The samples also exhibit a
magnetocaloric effect: around *T*_{C} of
Pr_{1−x}Ca_{x}MnO_{3} compounds,
magnetic-entropy change reaches the maximum values of about *5.0*,
*4.1*, and *2.5* J kg^{−1} K^{−1} for *x = 0.25*, *0.27*, and *0.29*,
respectively, under an applied-field change of *50*
kOe. Magnetic-field dependences of the maximum magnetic-entropy
change (Δ*S*_{max}) obey a power law |Δ*S*_{max}(H)| ∝ *H*^{n}, where exponent
values *n = 0.68 − 0.74* are close to those obtained from the
theoretical relation *n = 1 + (β − 1)/(β + γ)*.

### BibTeX Entry

@article{ho-2015-critical,

author = {T. A. Ho and T. D. Thanh and Y. Yu and D. M. Tartakovsky and T. O. Ho and P. D. Thang and A.-T. Le and T.-L. Phan and S. C. Yu},

title = {Critical behavior and magnetocaloric effect of Pr
$_{1-x}$
Ca
$_{x}$
MnO
$_{3}$
},

year = {2015},

urlpdf = {http://maeresearch.ucsd.edu/Tartakovsky/Papers/ho-2015-critical.pdf},

journal = { J. Appl. Phys.},

volume = {117},

number = {17},

doi = {10.1063/1.4914537},

pages = {17D122}

}