http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Chi Linh, Dinh,Thi Ha, Nguyen,Huu Duc, Nguyen,Giang Nam, Le Huu,Bau, Le Viet,Manh An, Nguyen,Yu, Seong-Cho,Dang Thanh, Tran Elsevier 2018 PHYSICA B-CONDENSED MATTER - Vol.532 No.-
<P><B>Abstract</B></P> <P>In this work, we have investigated the magnetic properties and the magnetocaloric effect of La<SUB>0.7−x</SUB>Na<SUB>x</SUB>Ca<SUB>0.3</SUB>MnO<SUB>3</SUB> compounds, which were prepared by a conventional solid-state reaction technique. The Rietveld refinement results suggested that the samples are single phase belonging to an orthorhombic structure (space group <I>Pnma</I>). Analyzing temperature dependence of magnetization <I>M</I>(<I>T</I>) revealed that the Curie temperature (<I>T</I> <SUB>C</SUB>) increases with increasing Na content (<I>x</I>). Their <I>T</I> <SUB>C</SUB> value is found to be 260–298K for <I>x</I>=0.0–0.1, respectively. Base on <I>M</I>(<I>T</I>) data measured at different applied magnetic fields (<I>H</I>), temperature dependence of magnetic entropy change Δ<I>S</I> <SUB>m</SUB>(<I>T</I>) data for all the samples was calculated by using a phenomenological model. In the vicinity of <I>T</I> <SUB>C,</SUB> -Δ<I>S</I> <SUB>m</SUB>(<I>T</I>) curve reaches a maximum value (denoted as |Δ<I>S</I> <SUB>max</SUB>|), which gradually increases with increasing <I>H</I>. Under 12kOe, the value of |Δ<I>S</I> <SUB>max</SUB>| is in a range of 1.47–5.19J/kgK corresponding to the relative cooling power RCP=57.12–75.88J/kg. Applied the universal master curve method for the magnetic entropy change, we concluded that Na-doped in La<SUB>0.7−x</SUB>Na<SUB>x</SUB>Ca<SUB>0.3</SUB>MnO<SUB>3</SUB> compounds leads to modification the nature of the magnetic phase transition from the first- to the second-order.</P>
Linh, Dinh Chi,Thanh, Tran Dang,Anh, Le Hai,Dao, Van Duong,Piao, Hong-Guang,Yu, Seong-Cho Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.725 No.-
<P><B>Abstract</B></P> <P>Influence of alkaline earth element doping in the A-site on the structure, magnetic and magnetocaloric properties of La<SUB>0.7</SUB>Ca<SUB>0.3-x</SUB>A<SUB>x</SUB>MnO<SUB>3</SUB> (A = Sr and Ba; <I>x</I> = 0, 0.15 and 0.3) perovskite manganites have been investigated. X-ray diffraction data indicates that samples <I>x</I> = 0 and 0.15 crystallize in the orthorhombic structure (space group <I>Pnma</I>), whereas samples <I>x</I> = 0.3 belong to the rhombohedral structure (space group <I>R</I>-3<I>c</I>). Substitution of Sr or Ba for Ca plays an important role in the increase of Curie temperature (<I>T</I> <SUB>C</SUB>) and modification the nature of the magnetic phase transition in materials. Sample <I>x</I> = 0 exhibits the first-order phase transition (FOPT) with a large magnetic entropy change (Δ<I>S</I> <SUB>m</SUB>), whereas samples <I>x</I> = 0.15 and 0.3 exhibit the second-order phase transition (SOPT) characterizations and the moderate values of Δ<I>S</I> <SUB>m</SUB>. Using the modified Arrott plots method, the critical behaviors around <I>T</I> <SUB>C</SUB> for SOPT samples have been investigated through the values of critical parameters (<I>T</I> <SUB>C</SUB>, <I>β</I>, <I>γ</I>, and <I>δ</I>). We pointed out that Ba-doping favors establishing long-range ferromagnetic order, contrary to the case of Sr-doping.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sr or Ba-doped La<SUB>0.7</SUB>Ca<SUB>0.3</SUB>MnO<SUB>3</SUB> leads to modify the nature of the phase transition. </LI> <LI> Ba-doping favors establishing long-range FM order, contrast with Sr-doping. </LI> <LI> The effective exponents vary non-monotonically in the asymptotic region. </LI> </UL> </P>
Tran Dang Thanh,Dinh Chi Linh,Tien Van Manh,Wen-Zhe Nan,Seong-Cho Yu,Hong-Guang Piao,Liqing Pan 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.3
In this work, we present a detailed study on the magnetic and the magnetocaloric properties of Sm0.5+xSr0.5−xMnO3 compounds with x = 0 − 0.1, which were prepared by using a solid-state reaction method. The x-dependent magnetic, as well as magnetocaloric, properties, including the magnetic phase transition, have been studied. The increase in Sm/Sr ratio plays an important role in controlling the Curie temperature (TC). We point out that all the samples undergo a first-order phase transition and exhibit a giant magnetocaloric effect. The magnetic entropy change (Sm) of samples was calculated based on isothermal M(H, T) data. The maximum value of Sm (denoted as |Smax|) at around TC is found to be 2.6 − 8.9 J·kg−1·K−1 for H = 30 kOe and depends on the value of x. We have also used the universal master curve method for the temperature dependences of Sm curves measured at different H values, Sm(T,H), to distinguish the magnetic order in the samples. Interestingly, none of the Sm(T,H) curves for the samples follow the universal master curve, Sm(T,H)/Smax versus = (T −TC)/(Tr−TC). As a consequence, a breakdown in the universal behavior of Sm(T,H)/Smax versus curve is another feature confirming a first-order phase-transition nature.
Tran Dang Thanh,Dinh Chi Linh,Le Viet Bau,Thi Anh Ho,Tien Van Manh,The-Long Phan,Seong-Cho Yu IEEE 2015 IEEE transactions on magnetics Vol.51 No.1
<P>Four samples of La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>Mn<SUB>0.92</SUB>Co<SUB>0.08</SUB>O<SUB>3</SUB> (LSMCO) with different crystallite sizes were prepared by the combination of solid-state reaction and mechanical milling methods. Based on isothermal magnetization data, M(H), temperature dependences of magnetic entropy change, ΔS<SUB>m</SUB>T, of the samples under a magnetic field change of 10 kOe were calculated. The maximum values of magnetic entropy change (|ΔS<SUB>max</SUB>|) at room temperature are in the range of 0.9-1.4 J · kg<SUP>-1</SUP> · K<SUP>-1</SUP>, corresponding to ferromagnetic (FM)-paramagnetic phase transition. In addition, M<SUP>2</SUP> versus H/M curves at temperatures around TC prove the samples exhibiting a second-order magnetic phase transition. The critical exponents β, γ, and δ were determined using the modified Arrott plot method and critical isotherm analysis. Here, these exponent values are located in between those expected for the mean-field theory and 3-D Heisenberg model. It means the coexistence of short-range and long-range FM interactions in LSMCO nanoparticles.</P>
Thanh, Tran Dang,Linh, Dinh Chi,Yen, Pham Duc Huyen,Bau, Le Viet,Ky, Vu Hong,Wang, Zhihao,Piao, Hong-Guang,An, Nguyen Manh,Yu, Seong-Cho Elsevier 2018 PHYSICA B-CONDENSED MATTER - Vol.532 No.-
<P><B>Abstract</B></P> <P>In this work, we present a detailed study on the magnetic properties and the magnetocaloric effect (MCE) of La<SUB>1−x</SUB>K<SUB>x</SUB>MnO<SUB>3</SUB> compounds with <I>x</I>=0.05–0.2. Our results pointed out that the Curie temperature (<I>T</I> <SUB>C</SUB>) could be controlled easily from 213 to 306K by increasing K-doping concentration (<I>x</I>) from 0.05 to 0.2. In the paramagnetic region, the inverse of the susceptibility can be analyzed by using the Curie-Weiss law, <I>χ</I>(<I>T</I>)=<I>C</I>/(<I>T</I>−<I>θ</I>). The results have proved an existence of ferromagnetic clusters at temperatures above <I>T</I> <SUB>C</SUB>. Based on Banerjee's criteria, we also pointed out that the samples are the second-order phase transition materials. Their magnetic entropy change was calculated by using the Maxwell relation and a phenomenological model. Interestingly, the samples with <I>x</I>=0.1–0.2 exhibit a large MCE in a range of 282–306K, which are suitable for room-temperature magnetic refrigeration applications. The composites obtained from single phase samples (<I>x</I>=0.1–0.2) exhibit the high relative cooling power values in a wide temperature range. From the viewpoint of the refrigerant capacity, the composites formed out of La<SUB>1−x</SUB>K<SUB>x</SUB>MnO<SUB>3</SUB> will become more useful for magnetic refrigeration applications around room-temperature.</P>