Abstract

We conducted a study of critical exponents to investigate the nature of paramagnetic to ferromagnetic phase transition in a La\(_{\mathrm{0.67}}\)Ba\(_{\mathrm{0.33}}\)MnO\(_{\mathrm{3}}\) (LBMO) film deposited on SrTiO\(_{\mathrm{3}}\). To this end, we performed dc magnetization M (H, T) measurements around the Curie temperature (\(T_{\mathrm{C}}\sim \) 276.5 K) within a temperature range that includes the critical region \(|\varepsilon |\) \(=\) \(|T-T_{\mathrm{C}}|\)/\(T_{\mathrm{C}} < 0.05\). We found that the transition is a second-order transition. Three main critical exponents, namely \(\beta \) (0.387), \(\gamma \) (1.309) and \(\delta \) (4.634), and the critical temperature \(T_{\mathrm{C}} =\) 276.6 K are derived from the modified Arrott plots. These exponents obey the Widom relation \(\delta =\) 1\(+\gamma \)/\(\beta \) and are able to collapse a bunch of isothermal magnetization data into two branches below and above \(T_{\mathrm{C}}\) based on the single scaling equation M(\({H, \varepsilon }\))\(\varepsilon ^{-\beta } = {f}_{\pm }({H} \varepsilon ^{({-\beta +\gamma })})\). The critical behavior in LBMO film is close to a 3D Heisenberg model, although certain long-range interactions still exist. Compared to a polycrystalline bulk sample, the long-range interactions are greatly suppressed, which may be attributed to the reduced dimensionality.

Graphic abstract

中文翻译：

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La $$ _ {0.67} $$ 0.67 Ba $$ _ {0.33} $$ 0.33 MnO $$ _ {3} $$ 3在SrTiO $$ _ {3} $$ 3上的3D-海森堡铁磁特性

摘要

我们对临界指数进行了研究，以研究La \（_ {\ mathrm {0.67}} \） Ba \（_ {\ mathrm {0.33}} \） MnO \（_ { \ mathrm {3}} \）（LBMO）膜沉积在SrTiO \（_ {\ mathrm {3}} \）上。为此，我们在包括临界区\（| \\）的温度范围内，在居里温度（\（T _ {\ mathrm {C}} \ sim \） 276.5 K）附近执行了直流磁化强度M（H，T）测量。 varepsilon | \）\（= \）\（| T-T _ {\ mathrm {C}} | \） / \（T _ {\ mathrm {C}} <0.05 \） 。我们发现过渡是二阶过渡。三个主要临界指数，即\（\ beta \）（0.387），\（\ gamma \）（1.309）和\（\ delta \）（4.634），以及临界温度\（T _ {\ mathrm {C}} = \） 276.6 K是从修改后的Arrott图得出的。这些指数服从Widom关系\（\ delta = \） 1 \（+ \ gamma \） / \（\ beta \）并能够将一堆等温磁化数据分解为\（T _ {\基于单个缩放方程M（\（{H，\ varepsilon} \）的mathrm {C}} \）\（\ varepsilon ^ {-\ beta} = {f} _ {\ pm}（{H} \ varepsilon ^ {（{-\ beta + \ gamma}}}）\）。LBMO影片中的临界行为接近3D Heisenberg模型，尽管某些远距离相互作用仍然存在。与多晶块状样品相比，远距离相互作用被大大抑制，这可能归因于尺寸的减小。

图形摘要