Electron paramagnetic resonance and electron‐nuclear double resonance study of Mn²⁺ ions in CdGeAs₂ crystals

Abstract

Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) . The Mn2+ ions substitute for the Cd 2+ ions in this tetragonal chalcopyrite lattice, and form "deep" isoelectronic centers. Their g values and crystal-field parameters are g ║ = 2.0025, g ⊥ = 2.0011, D = 118.8 MHz, a + 2/3F = 18.4 MHz, and a = −0.3 MHz. The hyperfine and nuclear electric quadrupole parameters for the 55 Mn nucleus are A ║ = −154.94 MHz, A ⊥ = −155.69 MHz, and P = 0.622 MHz. Hyperfine parameters for one set of nearby Cd nuclei and two sets of nearby As nuclei were also determined using ENDOR. No evidence was found in these doped bulk crystals to suggest that Mn 4+ ions substitute for Ge 4+ ions.

Transport peculiarities and phase transition in diluted magnetic semiconductors CdGeAs2: mn at high hydrostatic pressure

“…The dependence of Hall coefficient on pressure also has complex character. Hall coefficient does not vary almost up to P≈0.8 GPa, then increases until P<1.6GPa [6] and Mn 2+ substitutions for Cd 2+ in Mn-doped samples [7]. We are planning to conduct an additional study to clarify the nature of these anomalies.…”

Glass formation and optical properties of CdGeAs2 alloys

“…Early attempts at the growth of CGA single crystals were plagued with polycrystallinity, cracking, and poor optical transparency [2][3][4][5][6][7]. The more recent development of the horizontal gradient freeze growth of CGA single crystals from a melt using low temperature gradients has overcome most of these issues, resulting in large, crack-free single crystals with relatively low optical absorption [8][9][10][11].…”

“…Single crystals of this material have among the highest known non-linear optic coefficients (d 36 =236 pm/V) and a wide infrared transparency range (2.3-18 mm) [1][2][3][4][5][6][7][8][9][10][11]. Early attempts at the growth of CGA single crystals were plagued with polycrystallinity, cracking, and poor optical transparency [2][3][4][5][6][7].…”

Tricadmium Digermanium Tetraarsenide: A New Crystalline Phase Made with a Double‐Containment Ampoule Method

“…The large variations in the linear coefficients of thermal expansion between the a ‐axis (α L(a) ) and the c ‐axis (α L(c) ) tend to create strain gradients that lead to defects and cracking in large boules . Most of the early work with this material revealed issues with polycrystallinity, cracking, and poor optical properties, although recently, new processing techniques were developed to produce high purity single crystals using a horizontal gradient freeze growth method …”