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Excellent magnetocaloric properties in RE 2 Cu 2 Cd ( RE   =   Dy and Tm) compounds and its composite materials

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ABSTRACT

The magnetic properties and magnetocaloric effect (MCE) of ternary intermetallic RE2Cu2Cd (RE = Dy and Tm) compounds and its composite materials have been investigated in detail. Both compounds undergo a paramagnetic to ferromagnetic transition at its own Curie temperatures of TC ~ 48.5 and 15 K for Dy2Cu2Cd and Tm2Cu2Cd, respectively, giving rise to the large reversible MCE. An additionally magnetic transition can be observed around 16 K for Dy2Cu2Cd compound. The maximum values of magnetic entropy change (−ΔSMmax) are estimated to be 17.0 and 20.8 J/kg K for Dy2Cu2Cd and Tm2Cu2Cd, for a magnetic field change of 0–70 kOe, respectively. A table-like MCE in a wide temperature range of 10–70 K and enhanced refrigerant capacity (RC) are achieved in the Dy2Cu2Cd - Tm2Cu2Cd composite materials. For a magnetic field change of 0–50 kOe, the maximum improvements of RC reach 32% and 153%, in comparison with that of individual compound Dy2Cu2Cd and Tm2Cu2Cd. The excellent MCE properties suggest the RE2Cu2Cd (RE = Dy and Tm) and its composite materials could be expected to have effective applications for low temperature magnetic refrigeration.

No MeSH data available.


Normalized magnetic entropy change ΔS′ (=ΔSM/ΔSMmax) as a function of the rescaled temperature θ in the present temperature range for Tm2Cu2Cd compound.
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f6: Normalized magnetic entropy change ΔS′ (=ΔSM/ΔSMmax) as a function of the rescaled temperature θ in the present temperature range for Tm2Cu2Cd compound.

Mentions: where the Tr1 and Tr2 are the temperatures of the two reference points of each curve that correspond to 0.6ΔSMmax. The transformed ΔS′ (θ) curves for Tm2Cu2Cd and Dy2Cu2Cd compounds are displayed in Figs 6 and 7, respectively. We can note that all the rescaled ΔSM curves for Tm2Cu2Cd are overlapped with each other in the present temperature range, as shown in Fig. 6, proving the occurrence of the second order magnetic phase transition in Tm2Cu2Cd compound. In parallel, the curves for Dy2Cu2Cd compound are also overlapped with each other around and above TC (see Fig. 7). Whereas an obvious deviation below TC for θ < −2 (around TS) can be found which is properly due to the spin reorientation phenomenon or spin glass transition. Therefore, the ΔSM (T) around TS (5–30 K) are rescaled and the results are shown in the inset of Fig. 7. Similarly, the curves around TS are well overlapped with each other. Furthermore, the rescaled ΔS′ (θ) curves around TC and TS for Dy2Cu2Cd compound under various magnetic field changes are summarized together (as given in the Fig. 8). One can find that all the rescaled ΔSM curves can collapse onto one universal curve, which is consistent with the previous investigations that the materials with successive magnetic phase transitions22243031. The analysis of the universal behaviour further confirms that the Dy2Cu2Cd compound with the second order phase transition.


Excellent magnetocaloric properties in RE 2 Cu 2 Cd ( RE   =   Dy and Tm) compounds and its composite materials
Normalized magnetic entropy change ΔS′ (=ΔSM/ΔSMmax) as a function of the rescaled temperature θ in the present temperature range for Tm2Cu2Cd compound.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5035927&req=5

f6: Normalized magnetic entropy change ΔS′ (=ΔSM/ΔSMmax) as a function of the rescaled temperature θ in the present temperature range for Tm2Cu2Cd compound.
Mentions: where the Tr1 and Tr2 are the temperatures of the two reference points of each curve that correspond to 0.6ΔSMmax. The transformed ΔS′ (θ) curves for Tm2Cu2Cd and Dy2Cu2Cd compounds are displayed in Figs 6 and 7, respectively. We can note that all the rescaled ΔSM curves for Tm2Cu2Cd are overlapped with each other in the present temperature range, as shown in Fig. 6, proving the occurrence of the second order magnetic phase transition in Tm2Cu2Cd compound. In parallel, the curves for Dy2Cu2Cd compound are also overlapped with each other around and above TC (see Fig. 7). Whereas an obvious deviation below TC for θ < −2 (around TS) can be found which is properly due to the spin reorientation phenomenon or spin glass transition. Therefore, the ΔSM (T) around TS (5–30 K) are rescaled and the results are shown in the inset of Fig. 7. Similarly, the curves around TS are well overlapped with each other. Furthermore, the rescaled ΔS′ (θ) curves around TC and TS for Dy2Cu2Cd compound under various magnetic field changes are summarized together (as given in the Fig. 8). One can find that all the rescaled ΔSM curves can collapse onto one universal curve, which is consistent with the previous investigations that the materials with successive magnetic phase transitions22243031. The analysis of the universal behaviour further confirms that the Dy2Cu2Cd compound with the second order phase transition.

View Article: PubMed Central - PubMed

ABSTRACT

The magnetic properties and magnetocaloric effect (MCE) of ternary intermetallic RE2Cu2Cd (RE&thinsp;=&thinsp;Dy and Tm) compounds and its composite materials have been investigated in detail. Both compounds undergo a paramagnetic to ferromagnetic transition at its own Curie temperatures of TC ~ 48.5 and 15 K for Dy2Cu2Cd and Tm2Cu2Cd, respectively, giving rise to the large reversible MCE. An additionally magnetic transition can be observed around 16 K for Dy2Cu2Cd compound. The maximum values of magnetic entropy change (&minus;&Delta;SMmax) are estimated to be 17.0 and 20.8&thinsp;J/kg K for Dy2Cu2Cd and Tm2Cu2Cd, for a magnetic field change of 0&ndash;70&thinsp;kOe, respectively. A table-like MCE in a wide temperature range of 10&ndash;70&thinsp;K and enhanced refrigerant capacity (RC) are achieved in the Dy2Cu2Cd - Tm2Cu2Cd composite materials. For a magnetic field change of 0&ndash;50&thinsp;kOe, the maximum improvements of RC reach 32% and 153%, in comparison with that of individual compound Dy2Cu2Cd and Tm2Cu2Cd. The excellent MCE properties suggest the RE2Cu2Cd (RE&thinsp;=&thinsp;Dy and Tm) and its composite materials could be expected to have effective applications for low temperature magnetic refrigeration.

No MeSH data available.