1. Exchange bias and magnetocaloric effect in LaCr0. 9Ru0
Exchange bias and magnetocaloric effect in LaCr0.9Ru0.1O3 at low temperature
Subodh Kumar De
Department of Materials Science
Indian Association for the Cultivation of Science
Kolkata , INDIA

2. LaCrO3 G-type Antiferromagnet with TN = 292 K
Weak ferromagnetism due to spin canting
Modification of FM phase by substitution at Cr site
Replacement of Cr (3d) by Ru (4d)
Mixed magnetic (FM and AFM) phase
Oxidation state of Cr controls magnetic phase

3. Crystal structure: Orthorhombic
Single phase

4. Magnetization with temperature
Evidence of FM and AFM phases

5. XPS data
Mixed valency of Cr (2+ and 3+), Concentration: 37% (2+), 63% (3+)
Oxygen vacancy concentration 31%

6. Magnetic Exchange Interaction
Superexchange AFM Interaction
Cr3+(d3) - O - Cr3+(d3)
Cr2+(d4) – O – Cr2+(d4)
Double exchange FM Interaction
Cr3+(d3) - O – Cr2+(d4)
Cr3+(d3) – O – Ru4+(d4)

7. Exchange bias effect

8. Temperature Variation
Anomalous variation at around 100 K

9. Field Dependence Magnetic filed controls volume fraction of FM
and AFM phases

10. Entropy Calculation

11. Magnetocaloric Effect
Co existence of normal and inverse magneto caloric effect

12. SUMMARY Enhancement of FM component in AFM compound.
Large exchange bias field.
Co-existence of normal and inverse magnetocaloric
effect in same material.
Mixed valency and oxygen vacancy play important
roles to tune magnetic properties of LaCrO3 .

13. Thank you for your kind attention