A thermomagnetic generator which converts thermal energy to electrical energy without intermediate conversion to mechanical work, which works at temperatures in the range from -20°C to 200°C and comprises a series of at least three different metal-based materials whose magnetocaloric effect occurs at different temperatures, such that the conversion of thermal energy to electrical energy can exploit an enlarged temperature range, selected from compounds of the general formula (A y B 1-y) 2+δ C w D x E z where A is Mn or Co, B is Fe, Cr or Ni, C, D and E at least two of C, D and E are different, have a non-vanishing concentration and are selected from P, B, Se, Ge, Ga, Si, Sn, N, As and Sb, where at least one of C, D and E is Ge or Si, δ is a number in the range from -0.1 to 0.1, w, x, y, z are numbers in the range from 0 to 1, where w + x + z = 1; La- and Fe-based compounds of the general formulae and/or and/or La(Fe x Al 1-x) 13 H y or La(Fe x Si 1-x) 13 H y where x is a number from 0.7 to 0.95, y is a number from 0 to 3; La (Fe x Al y Co z) 13 or La(Fe x Si y Co z) 13 where x is a number from 0.7 to 0.95, y is a number from 0.05 to 1 - x, z is a number from 0.005 to 0.5; LaMn x Fe 2-x Ge where x is a number from 1.7 to 1.95 and Heusler alloys of the MnTP type where T is a transition metal and P is a p-doping metal having an electron count per atom e/a in the range from 7 to 8.5, Gd- and Si-based compounds of the general formula Gd 5 (Si x Ge 1-x) 4 where x is a number from 0.2 to 1, Fe 2 P-based compounds, manganites of the perovskite type, compounds which comprise rare earth elements and are of the general formulae and Tb 5 (Si 4-x Ge x) where x = 0, 1, 2, 3, 4, XTiGe where X = Dy, Ho, Tm, Mn- and Sb- or As-based compounds of the general formulae (VIII) and Mn 2-x Z x Sb (VIII) Mn 2 Z x Sb 1-x where Z is Cr, Cu, Zn, Co, V, As, Ge, x is from 0.01 to 0.5, where Sb may be replaced by As when Z is not As. compounds of the general formula (A y B 1-y) 2+δ C w D x E z where A is Mn or Co, B is Fe, Cr or Ni, C, D and E at least two of C, D and E are different, have a non-vanishing concentration and are selected from P, B, Se, Ge, Ga, Si, Sn, N, As and Sb, where at least one of C, D and E is Ge or Si, δ is a number in the range from -0.1 to 0.1, w, x, y, z are numbers in the range from 0 to 1, where w + x + z = 1; A is Mn or Co, B is Fe, Cr or Ni, C, D and E at least two of C, D and E are different, have a non-vanishing concentration and are selected from P, B, Se, Ge, Ga, Si, Sn, N, As and Sb, where at least one of C, D and E is Ge or Si, δ is a number in the range from -0.1 to 0.1, La- and Fe-based compounds of the general formulae and/or and/or La(Fe x Al 1-x) 13 H y or La(Fe x Si 1-x) 13 H y where x is a number from 0.7 to 0.95, y is a number from 0 to 3; La (Fe x Al y Co z) 13 or La(Fe x Si y Co z) 13 where x is a number from 0.7 to 0.95, y is a number from 0.05 to 1 - x, z is a number from 0.005 to 0.5; LaMn x Fe 2-x Ge where x is a number from 1.7 to 1.95 and x is a number from 0.7 to 0.95, y is a number from 0 to 3; x is a number from 0.7 to 0.95, y is a number from 0.05 to 1 - x, z is a number from 0.005 to 0.5; LaMn x Fe 2-x Ge x is a number from 1.7 to 1.95 and Heusler alloys of the MnTP type where T is a transition metal and P is a p-doping metal having an electron count per atom e/a in the range from 7 to 8.5, Gd- and Si-based compounds of the general formula Gd 5 (Si x Ge 1-x) 4 where x is a number from 0.2 to 1, Fe 2 P-based compounds, manganites of the perovskite type, compounds which comprise rare earth elements and are of the general formulae and Tb 5 (Si 4-x Ge x) where x = 0, 1, 2, 3, 4, XTiGe where X = Dy, Ho, Tm, Mn- and Sb- or As-based compounds of the general formulae (VIII) and Mn 2-x Z x Sb (VIII) Mn 2 Z x Sb 1-x where Z is Cr, Cu, Zn, Co, V, As, Ge, x is from 0.01 to 0.5, where Sb may be replaced by As when Z is not As. Z is Cr, Cu, Zn, Co, V, As, Ge, x is from 0.01 to 0.5,