Pressure and magnetic field dependence of valence and magnetic transitions in EuPtP.
← Research streamIn EuPtP, high-field analysis indicates about half of Eu is divalent at the lowest temperature, with the number of Eu2+ increasing discontinuously at T2 and T1 as temperature increases. Applying pressure shifts T1 and T2 to higher temperatures and suppresses …
Study snapshot
Abstract
The hexagonal layered compound, EuPtP, exhibits two valence transitions, at T₁ = 235 K and T₂ = 190 K, and an antiferromagnetic order at T(N) = 8.6 K. We have examined the effects of magnetic field and pressure, and the specific heat. Analysis of the high-field experiments confirms that half of Eu are in a divalent state at the lowest temperature, and that the number of Eu(² + ) increases discontinuously at T₂ and T₁ with increasing temperature. The magnetic entropy reaches ~ 22 J K⁻¹ mol⁻¹ at room temperature, which is larger than that expected for J = 7/2 of Eu(²+ ) (17.3 J K⁻¹ mol⁻¹). This is in good agreement with the magnetic entropy deduced from the interconfigurational fluctuation model, which explains the valence transition in Eu(Pd(₁- x)Pt(x))₂Si₂. The application of pressure shifts T₁ and T₂ higher and suppresses the intermediate phase (β phase, T₂ < T < T₁), whereas it does not change the properties of the low-temperature phase (γ phase, T < T₂) and the T(N).
AI evidence extraction
Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.
Main findings
In EuPtP, high-field analysis indicates about half of Eu is divalent at the lowest temperature, with the number of Eu2+ increasing discontinuously at T2 and T1 as temperature increases. Applying pressure shifts T1 and T2 to higher temperatures and suppresses the intermediate (β) phase, while not changing the low-temperature (γ) phase properties or TN.
Outcomes measured
- valence transitions (T1=235 K, T2=190 K)
- antiferromagnetic ordering temperature (TN=8.6 K)
- specific heat
- magnetic entropy
- pressure dependence of phase transitions
View raw extracted JSON
{
"study_type": "other",
"exposure": {
"band": null,
"source": "magnetic field (laboratory, material study)",
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"outcomes": [
"valence transitions (T1=235 K, T2=190 K)",
"antiferromagnetic ordering temperature (TN=8.6 K)",
"specific heat",
"magnetic entropy",
"pressure dependence of phase transitions"
],
"main_findings": "In EuPtP, high-field analysis indicates about half of Eu is divalent at the lowest temperature, with the number of Eu2+ increasing discontinuously at T2 and T1 as temperature increases. Applying pressure shifts T1 and T2 to higher temperatures and suppresses the intermediate (β) phase, while not changing the low-temperature (γ) phase properties or TN.",
"effect_direction": "unclear",
"limitations": [],
"evidence_strength": "insufficient",
"confidence": 0.74,
"peer_reviewed_likely": "yes",
"keywords": [
"EuPtP",
"valence transition",
"antiferromagnetism",
"magnetic field dependence",
"pressure dependence",
"specific heat",
"magnetic entropy",
"interconfigurational fluctuation model"
],
"suggested_hubs": []
}AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.
Identifiers and source
DOI: 10.1088/0953-8984/22/22/226003
PubMed: 21393754