Speaker
Description
The discovery of unconventional superconductivity (SC) in doped iron-based arsenide BaFe$_2$As$_2$ [1] crystallizing in ThCr$_2$Si$_2$-type structure ignited interest in 122 tetragonal systems. Substituting iron with other 3$d$ or 4$d$ transition metal ions that constitute the metal-pnictide sublattice in similar systems have yielded interesting results including, but not limited to, low-temperature SC [2], half-metallic behaviour [3], new layered magnetic phases [4] and highly frustrated itinerant magnetism [5]. The Mn based BaMn$_2$$Pn_{2}$ compounds [$Pn$ = P, As, Sb, Bi] are small band gap semiconductors with stacked-square-lattice of Mn ions that order antiferromagnetically at temperatures higher than room temperature. Although As, Sb and Bi based compounds have been thoroughly investigated [6-9], the experimental work on BaMn$_2$P$_2$ is dated and limited [10,11]. In this contribution, we report the synthesis and growth of single crystals of BaMn$_2$P$_2$ as well as its structural, electronic, magnetic and thermal properties. Electrical resistivity and heat capacity measurements indicate that BaMn$_2$P$_2$ has an insulating ground state with a small band gap. Anisotropic magnetic susceptibility measurements show that similar to its As-, Sb- and Bi- counterparts, BaMn$_2$P$_2$ has collinear Néel type antiferromagnetism below $T_{\rm N}$ = 795(15) K, which is the highest value for 122- pnictide compounds reported so far. The magnetic susceptibility increases above $T_{\rm N}$ suggesting that antiferromagnetic correlations persist above the magnetic ordering temperature—a feature which was also observed in the As-, Sb- and Bi- based compounds. This can be explored further through hole-doping studies as in the case of BaMn$_2$As$_2$ with $T_{\rm N}$ = 618 K, which resulted in half-metallic behaviour with $T_{\rm c}$ = 100 K which is of significance as high $T_{\rm c}$ half-metals are ideal for spin-polarized transport-based applications. These results were recently published in Phys. Rev. Mater. 7, 044410 (2023).
[1] D. C. Johnston, Adv. Phys. 59, 803 (2010).
[2] V. K. Anand, H. Kim, M. A. Tanatar, R. Prozorov, and D. C. Johnston, Phys. Rev. B 87, 224510 (2013).
[3] A. Pandey and D. C. Johnston, Phys. Rev. B 92, 174401 (2015).
[4] A. Pandey, S. L. Samal, and D. C. Johnston, Inorg. Chem. 57, 3206 (2018).
[5] A. Sapkota, B. G. Ueland, V. K. Anand, N. S. Sangeetha, D. L. Abernathy, M. B. Stone, J. L Niedziela, D. C. Johnston, A. Kreyssig, A. I. Goldman, and R. J. McQueeney, Phys. Rev. Lett. 119, 147201 (2017).
[6] Y. Singh, A. Ellern, and D. C. Johnston, Phys. Rev. B 79, 094519 (2009).
[7] N. S. Sangeetha, V. Smetana, A.-V. Mudring, and D. C. Johnston, Phys. Rev. B 97, 014402 (2018).
[8] B. Saparov and A. S. Sefat, J. Solid State Chem. 204, 32 (2013).
[9] S. Calder, B. Saparov, H. B. Cao, J. L. Niedziela, M. D. Lumsden, A. S. Sefat, and A. D. Christianson, Phys. Rev. B 89, 064417 (2014).
[10] S. L. Brock, J. E. Greedan, and S. M. Kauzlarich, J. Solid State Chem. 109, 416 (1994).
[11] S. L. Brock, J. E. Greedan, and S. M. Kauzlarich, J. Solid State Chem. 113, 303 (1994).
Level for award;(Hons, MSc, PhD, N/A)?
N/A
| Apply to be considered for a student ; award (Yes / No)? | No |
|---|
