diff --git a/schema/core/reusable/frequency_function_matrix.json b/schema/core/reusable/frequency_function_matrix.json
new file mode 100644
index 000000000..5086acde1
--- /dev/null
+++ b/schema/core/reusable/frequency_function_matrix.json
@@ -0,0 +1,23 @@
+{
+    "$id": "core/reusable/frequency-function-matrix",
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "title": "",
+    "description": "Schema for a function of frequency yielding a nx3 matrix",
+    "type": "object",
+    "properties": {
+        "frequencies": {
+            "description": "Frequencies",
+            "type": "array",
+            "items": {
+                "type": "number"
+            }
+        },
+        "components": {
+            "description": "Matrix with 3 columns, e.g. x, y, z",
+            "type": "array",
+            "items": {
+                "$ref": "../primitive/array_of_3_numbers.json"
+            }
+        }
+    }
+}
diff --git a/schema/properties_directory/non-scalar/dielectric_tensor.json b/schema/properties_directory/non-scalar/dielectric_tensor.json
index 12599880c..823836ea4 100644
--- a/schema/properties_directory/non-scalar/dielectric_tensor.json
+++ b/schema/properties_directory/non-scalar/dielectric_tensor.json
@@ -10,32 +10,17 @@
         },
         "diagonalReal": {
             "description": "Real parts of the dielectric tensor diagonal components",
-            "$ref": "#/definitions/dielectric-function"
+            "$ref": "../../core/reusable/frequency_function_matrix.json"
         },
         "diagonalImaginary": {
             "description": "Imaginary parts of the dielectric tensor diagonal components",
-            "$ref": "#/definitions/dielectric-function"
+            "$ref": "../../core/reusable/frequency_function_matrix.json"
+        },
+        "spin": {
+            "type": "number"
         }
     },
-    "definitions": {
-        "dielectric-function": {
-            "type": "object",
-            "properties": {
-                "frequencies": {
-                    "description": "Frequencies in eV",
-                    "type": "array",
-                    "items": {
-                        "type": "number"
-                    }
-                },
-                "dielectricComponents": {
-                    "description": "Dielectric components, e.g. espr_x, espr_y, espr_z",
-                    "type": "array",
-                    "items": {
-                        "$ref": "../../core/primitive/array_of_3_numbers.json"
-                    }
-                }
-            }
-        }
-    }
+    "required": [
+        "name"
+    ]
 }