Exploring Magnetic, Dielectric, and specific heat capacity coupling in (LaMnO3)0.5 -(BaTiO3)0.5 Composites

Sagar Mal Kumawat^1*, G. D. Dwivedi¹, A. Tiwari³, D. C. Kakarla³, H. D. Yang³, H. Chou³, E.-P. Liu⁴, W.-T. Chen⁴, C.-L. Huang^1,5,6

¹Department of Physics, National Cheng Kung University, Tainan, Taiwan
²Department of Physics, Kalinga University, Atal-Nagar, Nava Raipur, Chhattisgarh, India
³Department of Physics and Center of Crystal Research, National Sun Yat-sen University, Kaohsiung City, Taiwan
⁴Center for Condensed Matter Sciences, , National Taiwan University, Taipei, Taiwan
⁵Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan, Taiwan
⁶Taiwan Consortium of Emergent Crystalline Materials, National Science and Technology Council, Taipei, Taiwan

* Presenter:Sagar Mal Kumawat, email:kumawat123sagar@gmail.com

This study investigates the structural, magnetic, dielectric, and thermal properties of the (LaMnO3)0.5 - (BaTiO3)0.5 composite system. X-ray diffraction patterns analysis revealed that the composite crystallizes in a cubic structure with space group Pm3 ̅m. The system contains two distinct phases of LaMnO3 and BaTiO3 without any interdiffusion of phases. Mn L₂,₃- and Ti L₂,₃-edge X-ray absorption spectroscopy reveals the exclusive presence of Mn³⁺ and Ti⁴⁺ oxidation states, confirming phase purity and the absence of mixed-valency states, which could otherwise alter the system’s magnetic and dielectric properties. Magnetic susceptibility measurements indicate an antiferromagnetic transition at approximately 12 K, which aligns with the observed anomaly in the dielectric constant near 11 K, suggesting magneto-dielectric coupling within the composite. Notably, dielectric measurements at room temperature show a high dielectric constant (~12,000 F/m), significantly enhancing the value for pure BaTiO3 (~2,000 F/m). This enhancement is likely attributed to interfacial polarization effects resulting from the interaction between LaMnO3 and BaTiO3 phases. Specific heat measurements observed an anomaly at 45 K and a small kink at 10 K, which indicate the presence of a weak coupling between magnetic ordering and specific heat capacity, which corresponds to a multifunctional response under thermal variation. These findings emphasize the potential of (LaMnO3)0.5 - (BaTiO3)0.5 composites for applications requiring tunable dielectric properties and magneto-dielectric coupling, especially in low-temperature multifunctional devices.

Keywords: Magneto-dielectric coupling, Specific heat Capacity , Composite system