最近的研究表明,在低温低场时,Gd_5Ge_4的一级磁结构相变被阻止而进入一种磁玻璃态,即在反铁磁母体中随机分布着铁磁团簇.结合这一最新研究结果,通过对Gd_5Ge_4样品不同低温的磁场诱导的磁化强度进行两次循环测量,研究发现在不同条件下Gd_5Ge_4的磁结构相变存在可逆性与不可逆性,并结合磁玻璃态进行了分析讨论.验证了Gd_5Ge_4的等温磁化行为和结构变化的一致性,这为证明在磁和晶格之间存在耦合作用提供了直接的实验证据,揭示了一级磁结构相变对巨磁热效应的产生起了重要作用.
Recent research have shown that the first order magnetic structural transition in Gd_5Ge_4 can be arrested at low temperatures and low magnetic fields.This effect gives rise to a low temperature magnetic glass state with ferromagnetic clusters embedded in antiferromagnetic matrix.Based on this new result,we have found that Gd_5Ge_4 undergoes reversible and irreversible magnetic structural phase transformations in different measuring conditions.It is shown that the magnetic behaviors are related to the structure transition.The first order magnetic structural phase transition plays an important role to the giant magnetocaloric effect.
参考文献
| [1] | Jensen J;Mackintosh A R .[J].Physical Review Letters,1990,64:2699-2702. |
| [2] | Alkhafaji M T;Ali N.Magnetic Phase Diagram of Dysprosium[M].Lausanne:Elsevier Science Sa,1997:659-661. |
| [3] | Pecharsky VK;Gschneidner KA .Giant magnetocaloric effect in Gd-5(Si2Ge2)[J].Physical review letters,1997(23):4494-4497. |
| [4] | Morellon L;Algarabel P A;Ibarra M R et al.[J].Physical Review B:Condensed Matter,1998,58:14721-14724. |
| [5] | Levin E M;Pecharsky V K;Gschneidner K A .[J].Physical Review B:Condensed Matter,2000,62:14625-14628. |
| [6] | Levin E M;Pecharsky A O;Pecharsky V K et al.[J].Physical Review B:Condensed Matter,2001,63:10. |
| [7] | Choe W.;Pecharsky AO.;Gschneidner KA.;Young VG.;Miller GJ.;Pecharsky VK. .Making and breaking covalent bonds across the magnetic transition in the giant magnetocaloric material Gd-5(Si2Ge2)[J].Physical review letters,2000(20):4617-4620. |
| [8] | Gschneidner K A;Pecharsky A;Dennis K W .[J].Journal of Alloys and Compounds,1997,260:107-110. |
| [9] | Morellon L;Blasco J;Algarabel P A et al.[J].Physical Review B:Condensed Matter,2000,62:1022-1026. |
| [10] | Levin E M;Gschneidner K A;Pecharsky V K .[J].Physical Review B:Condensed Matter,2002,65:5. |
| [11] | Magen C.;Morellon L.;Algarabel PA.;Marquina C.;Ibarra MR. .Magnetoelastic behaviour of Gd5Ge4[J].Journal of Physics. Condensed Matter,2003(14):2389-2397. |
| [12] | Levin E M;Pecharsky V K;Gschneidner K A et al.[J].Physical Review B:Condensed Matter,2001,64:11. |
| [13] | Pecharsky V K;Holm A P;Gschneidner K A et al.[J].Physical Review Letters,2003,91:4. |
| [14] | Roy S B;Chattopadhyay M K;Chaddah P et al.[J].Physical Review B:Condensed Matter,2006,74:4. |
| [15] | Gschneidner KA;Pecharsky VK;Tsokol AO .Recent developments in magnetocaloric materials[J].Reports on Progress in Physics,2005(6):1479-1539. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%