Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Comparison of the obtained data with the literature_
| Chemical composition | TC [K] | −DS : B | Preparation method | Year |
|---|---|---|---|---|
| Mn1.1Fe0.9P0.81Ge0.19 | 260 | 14 J/kg K : 2 T | bulk (mechanical alloying) | 2008[4] |
| Mn1.1Fe0.9P0.78Ge0.22 | 298 | 20 J/kg K : 2 T | ||
| Mn1.1Fe0.9P0.75Ge0.25 | 330 | 13 J/kg K : 2 T | ||
| Mn1.1Fe0.9P0.8Ge0.2 | 206 | 15 J/kg K : 2 T | ribbon bulk alloy (induction) ribbon | 2006[5] |
| Mn1.1Fe0.9P0.76Ge0.24 | 299 | 11 J/kg K : 2 T | ||
| Mn1.1Fe0.9P0.76Ge0.24 | 317 | 17 J/kg K : 2 T | ||
| Mn1.1Fe0.9P0.8Ge0.2 | 255 | 28 J/kg K : 2 T | bulk (mechanical alloying) | 2009[6] |
| Mn1.1Fe0.9P0.8Ge0.2 | 250 | 22 J/kg K : 2 T | bulk (mechanical alloying) | 2010[7] |
| MnFeP0.7Ge0.3 | 360 | − | bulk (mechanical alloying) | 2004[8] |
| MnFeP0.5Ge0.5 | 570 | |||
| Mn1.1Fe0.9P0.74Ge0.26 | 323 | 45 J/kg K : 5 T | ribbons (arc melting + melt spinning) | 2015[9] |
| Mn1.1Fe0.9P0.7Ge0.3 | 360 | 19 J/kg K : 5 T | ||
| Mn1.1Fe0.9P0.68Ge0.32 | 403 | 9 J/kg K : 5 T | ||
| Mn1.1Fe0.9P0.7Ge0.3 | 380 | − | bulk (mechanical alloying) | 2005[10] |
| Mn1.15Fe0.85P0.76Ge0.25 | 263 | 10 J/kg K : 2 T | bulk (arc melting) | 2015[11] |
| Mn1.15Fe0.85P0.74Ge0.26 | 272 | − | ||
| Mn1.15Fe0.85P0.72Ge0.28 | 314 | − | ||
| Mn1.15Fe0.85P0.70Ge0.30 | 330 | 12 J/kg K : 2 T | ||
| Mn1.15Fe0.85P0.68Ge0.32 | 342 | 12 J/kg K : 2 T | ||
| Mn1.05Fe0.95P0.81Ge0.19 | 295 | 9 J/kg K : 2 T | bulk (solid-state reaction) | this work |
| Mn1.05Fe0.95P0.79Ge0.21 | 310 | − | ||
| Mn1.05Fe0.95P0.78Ge0.22 | 335 | 7 J/kg K : 2 T | ||
| Mn1.1Fe0.9P0.78Ge0.22 | 318 | − | ||
| Mn1.17Fe0.83P0.78Ge0.22 | 293 | 9 J/kg K : 2 T |
Peak temperatures and Avrami kinetic parameters derived for two measured samples with different heating rates_ F – rate of heating, Tp – peak transformation temperature, ln(k’) – rate constant logarithm, n – Avrami exponent, t1/2 – half-time of transformation_
| Φ [K/min] | Tp [K] | ln(k’) | n | t1/2 [min] |
|---|---|---|---|---|
| Mn1.05Fe0.95P0.78Ge 0.22 | ||||
| 30 | 342.48 | (8.59±0.27) × 10−2 | 4.31±0.11 | 0.900 |
| 25 | 342.33 | 7.38±0.28) × 10−2 | 4.26±0.12 | 0.902 |
| 20 | 341.85 | (5.60±0.30) × 10−2 | 4.07±0.12 | 0.901 |
| 15 | 341.71 | (−4.31±2.47) × 10−3 | 4.24±0.13 | 0.918 |
| 10 | 341.57 | (−2.11±0.07) × 10−1 | 4.38±0.16 | 0.965 |
| 5 | 340.79 | − 1.01±0.04 | 4.46±0.19 | 1.155 |
| Mn1.05Fe0.95P0.81Ge 0.19 | ||||
| 30 | 305.27 | (3.37±0.09) × 10−2 | 5.24±0.08 | 0.926 |
| 25 | 304.98 | (2.10±0.50) × 10−2 | 5.18±0.12 | 0.928 |
| 20 | 304.64 | (−5.37±0.10) ×10−2 | 5.27±0.11 | 0.942 |
| 15 | 304.30 | (−1.41±0.03) × 10−1 | 4.87±0.11 | 0.955 |
| 10 | 303.90 | (−4.71±0.10) × 10−1 | 5.25±0.12 | 1.020 |
| 5 | 303.28 | −1.66±0.04 | −5.27±0.13 | 1.278 |
Weight fractions of refined phases, room temperature lattice parameters, c/a ratio and unit-cell volume for Fe2P-type phase_ Sample 3 is in the low-temperature ferromagnetic state_
| No. | Fe2P-type [%] | MnO [%] | Fe3Mn4Ge6[%] | a = b [Å] | c [Å] | c/a ratio | V[ Å3] |
|---|---|---|---|---|---|---|---|
| 1 | 87.97±0.74 | 6.45±0.53 | 5.57±0.17 | 6.0795±0.0006 | 3.4515±0.0004 | 0.5677 | 110.476±0.021 |
| 2 | 87.53±1.03 | 6.57±1.14 | 5.90±0.32 | 6.1016±0.0014 | 3.4421±0.0010 | 0.5641 | 110.979±0.049 |
| 3 | 83.05±1.07 | 12.20±0.97 | 4.75±0.21 | 6.1765±0.0011 | 3.3514±0.0006 | 0.5426 | 110.724±0.034 |
| 4 | 80.97±1.04 | 12.45±0.98 | 6.58±0.22 | 6.1038±0.0009 | 3.4441±0.0006 | 0.5704 | 111.123±0.030 |
| 5 | 81.83±1.39 | 14.24±0.93 | 3.93±0.18 | 6.1118±0.0008 | 3.4429±0.0005 | 0.5633 | 111.375±0.027 |