Negative thermal expansion (NTE) is a notable physical property where a material’s volume decreases instead of increasing when heated. The identification of NTE materials is crucial for thermal expansion control engineering. Most NTE materials exhibit NTE only within a narrow temperature range, restricting their applications. Achieving NTE across a broad temperature range remains a significant challenge. This study developed a novel PbTiO3-based system, (1-x)PbTiO3–xBiLuO3, incorporating rare-earth elements, using a distinctive high-pressure and high-temperature synthesis technique. We achieved NTE across a broad temperature range by coupling lattice (c/a) with ferroelectric order parameters. The incorporation of BiLuO3 resulted in distinctive ferroelectric characteristics, including increased tetragonality, spontaneous polarization, and NTE over a broad temperature range. NTE over an extended temperature range has been achieved in 0.95PbTiO3–0.05BiLuO3 (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12598_2025_3310_Article_IEq1.gif" Format="GIF" Height="15" Rendition="HTML" Resolution="72" Type="Linedraw" Width="21" /> </InlineMediaObject> <EquationSource Format="TEX">$\overline{\alpha }_{{\text{V}}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mover> <mi>α</mi> <mo>¯</mo> </mover> <mtext>V</mtext> </msub> </math></EquationSource> </InlineEquation> = −1.7 × 10–5 K−1, 300–840 K) and 0.90PbTiO3–0.10BiLuO3 (<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12598_2025_3310_Article_IEq1.gif" Format="GIF" Height="15" Rendition="HTML" Resolution="72" Type="Linedraw" Width="21" /> </InlineMediaObject> <EquationSource Format="TEX">$\overline{\alpha }_{{\text{V}}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mover> <mi>α</mi> <mo>¯</mo> </mover> <mtext>V</mtext> </msub> </math></EquationSource> </InlineEquation> = −1.4 × 10–5 K−1, 300–860 K), compared to pristine PbTiO3 (<InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12598_2025_3310_Article_IEq1.gif" Format="GIF" Height="15" Rendition="HTML" Resolution="72" Type="Linedraw" Width="21" /> </InlineMediaObject> <EquationSource Format="TEX">$\overline{\alpha }_{{\text{V}}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mover> <mi>α</mi> <mo>¯</mo> </mover> <mtext>V</mtext> </msub> </math></EquationSource> </InlineEquation> = −1.99 × 10–5 K−1, 300–763 K). The improved tetragonalities and broader NTE temperature range result from the strong hybridization of Pb/Bi–O and Ti/Lu–O atoms, as demonstrated by combined experimental and theoretical analyses, including high-energy synchrotron X-ray diffraction, Raman spectroscopy, and density functional theory calculations. This study introduces a novel example of NTE over a broad temperature range, highlighting its potential as a high-performance thermal expansion compensator. Additionally, it presents an effective method for incorporating rare-earth elements to achieve NTE in PbTiO3-based perovskites across a wide temperature range. Graphical abstract

Achieving negative thermal expansion over an extended temperature range in rare-earth-modified PbTiO₃-based perovskites

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发表日期：

2025年6月12日

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Zhao Pan,
Meng-Qi Ye,
Yan Suo,
Feng-Yi Zhou,
Duo Wang,
Jin Liu,
Xu-Bin Ye,
Jie Zhang,
Mao-Cai Pi,
Wei-Hao Li,
Chao Chen,
Nian-Peng Lu,
Shogo Kawaguchi,
Yao Shen,
You-Wen Long

摘要

Negative thermal expansion (NTE) is a notable physical property where a material’s volume decreases instead of increasing when heated. The identification of NTE materials is crucial for thermal expansion control engineering. Most NTE materials exhibit NTE only within a narrow temperature range, restricting their applications. Achieving NTE across a broad temperature range remains a significant challenge. This study developed a novel PbTiO₃-based system, (1-x)PbTiO₃–xBiLuO₃, incorporating rare-earth elements, using a distinctive high-pressure and high-temperature synthesis technique. We achieved NTE across a broad temperature range by coupling lattice (c/a) with ferroelectric order parameters. The incorporation of BiLuO₃ resulted in distinctive ferroelectric characteristics, including increased tetragonality, spontaneous polarization, and NTE over a broad temperature range. NTE over an extended temperature range has been achieved in 0.95PbTiO₃–0.05BiLuO₃ ( $\overline{\alpha }_{{\text{V}}}$ ${\bar{α}}_{V}$ = −1.7 × 10^–5 K⁻¹, 300–840 K) and 0.90PbTiO₃–0.10BiLuO₃ ( $\overline{\alpha }_{{\text{V}}}$ ${\bar{α}}_{V}$ = −1.4 × 10^–5 K⁻¹, 300–860 K), compared to pristine PbTiO₃ ( $\overline{\alpha }_{{\text{V}}}$ ${\bar{α}}_{V}$ = −1.99 × 10^–5 K⁻¹, 300–763 K). The improved tetragonalities and broader NTE temperature range result from the strong hybridization of Pb/Bi–O and Ti/Lu–O atoms, as demonstrated by combined experimental and theoretical analyses, including high-energy synchrotron X-ray diffraction, Raman spectroscopy, and density functional theory calculations. This study introduces a novel example of NTE over a broad temperature range, highlighting its potential as a high-performance thermal expansion compensator. Additionally, it presents an effective method for incorporating rare-earth elements to achieve NTE in PbTiO₃-based perovskites across a wide temperature range.

Graphical abstract

Achieving negative thermal expansion over an extended temperature range in rare-earth-modified PbTiO3-based perovskites

摘要

Achieving negative thermal expansion over an extended temperature range in rare-earth-modified PbTiO₃-based perovskites