Giant barocaloric effect in all- d -metal Heusler shape memory alloys

Abstract

We have studied the barocaloric properties associated with the martensitic transition of a shape memory Heulser alloy Ni50Mn31.5Ti18.5 which is composed of all-d-metal elements. The composition of the sample has been tailored to avoid long range ferromagnetic order in both ausenite and martensite. The lack of ferromagnetism results in a weak magnetic contribution to the total entropy change thereby leading to a large transition entropy change. The combination of such a large entropy change and a relatively large volume change at the martensitic transition gives rise to giant barocaloric properties in this alloy. When compared to other shape memory Heusler alloys, our material exhibits values for adiabatic temperature and isothermal entropy changes significantly larger than values reported so far for this class of materials. Furthermore, our Ni50Mn31.5Ti18.5 also compares favourably to the best state-of-the-art magnetic barocaloric materials.

Colossal and Reversible Barocaloric Effect in Phase Change Materials n-Alkanes

“…2A and Fig. 2B for CnH2n+2 (n=14, 16 and 18) along with those reported for existing BC materials 10,[13][14][15][16][17]20,21,[29][30][31][32][33][34][35][36][37][38][39] . Here, the isothermal entropy change in references is mainly obtained by indirect method or quasi-direct method 6 .…”

Reversible colossal barocaloric effects near room temperature in 1-X-adamantane (X=Cl, Br) plastic crystals

“…(b)Reversible adiabatic temperature changes upon 0 → ~1 kbar pressure increase as a function of temperature. Literature data taken from: PG:[12]; C60:[13];[TPrA][Mn(dca)3]:[44]; [(CH3)4N]Mn[N3]3:[45]; MnCoGeB0.03 (asterisk):[46]; (MiNiSi)0.60(FeCoGe)0.40 (diamond) and (MiNiSi)0.61(FeCoGe)0.39 (triangle):[47]; Ni50Mn31.5Ti18.5 (circle):[48].…”

Martensitic transformation and magnetocaloric effect in Mn<sub>50</sub>Ni<sub>32</sub><sub>–</sub><sub><italic>x</italic></sub>Cu<sub><italic>x</italic></sub>Co<sub>8</sub>Ti<sub>10</sub> Heusler alloy ribbons

“…合适成 分的该系列合金马氏体相变既属于热弹性相变, 又属 于铁磁性相变, 因此既可以被温度或应力诱导, 也可 以被磁场驱动. 在温度、磁场等外界因素的激励下, 合金可以发生铁磁奥氏体和弱磁马氏体之间的马氏体 相变(或逆马氏体相变), 晶体结构转变和磁性相变强 烈耦合, 因此, 相变附近表现出很大的磁热效应 [2][3][4] , 同 时 也 具 有 很 大 的 机 械 热 效 应 ( 弹 热 、 压 热 ) 、 巨 磁 电阻、磁致应变、交换偏置、动力学囚禁等物理效 应 [2][3][4][10][11][12][13][14][15][16][17][18][19][20][21][22][23] , 从而在固态制冷、磁激励、人工智能等前 沿和新兴领域都极具应用前景.…”

“…人们在对Ni-Mn基FSMAs研究的过程中, 通过多 种途径调控实现铁磁/弱磁性马氏体相变, 比如过渡/ 主族元素取代 [2][3][4][8][9][10]14,15,[18][19][20][21][22][23] 、热处理 [11] 、改变快淬 速度 [13] 、间隙位原子掺杂 [16,17] 等. 人们也提出各种机 制解释马氏体相变调控的物理机理, 比如应力弛 豫 [11] 、反位缺陷 [11] 、Mn-Mn间距 [2] 、价电子浓度 [8] 、 第二相析出 [11,13] 等.…”

“…人们也提出各种机 制解释马氏体相变调控的物理机理, 比如应力弛 豫 [11] 、反位缺陷 [11] 、Mn-Mn间距 [2] 、价电子浓度 [8] 、 第二相析出 [11,13] 等. 比如, 2009年, Liu等人 [11] 发现2 h [14,15,18,19] 、弹热 效应 [17,21] 、压热效应 [16,20] 、磁电阻 [14,15,19] 、磁致应 变 [14,15] 、交换偏置 [22] 等, 从而引起人们的广泛重视和 研究. 然而目前对此类合金研究得还不够充分, 且相 关研究大多都集中在富Ni基all-d Ni-Co-Mn-Ti体系的 块材 [14][15][16][17]20,21] 、薄膜 [22] 、条带 [18,19,23] .…”