diff --git a/nifty/field.py b/nifty/field.py
index ab647ab8fdee61da005869afe749e8bf5783c6f9..3eeb61c050d40040ad87e096f073d5aa1ffa7cf1 100644
--- a/nifty/field.py
+++ b/nifty/field.py
@@ -358,7 +358,7 @@ class Field(Loggable, Versionable, object):
                 self.domain_axes[space_index])
 
         harmonic_domain = self.domain[space_index]
-        power_domain = PowerSpace(harmonic_domain=harmonic_domain,
+        power_domain = PowerSpace(harmonic_partner=harmonic_domain,
                                   distribution_strategy=distribution_strategy,
                                   logarithmic=logarithmic, nbin=nbin,
                                   binbounds=binbounds)
@@ -512,7 +512,7 @@ class Field(Loggable, Versionable, object):
         result_domain = list(self.domain)
         for power_space_index in spaces:
             power_space = self.domain[power_space_index]
-            harmonic_domain = power_space.harmonic_domain
+            harmonic_domain = power_space.harmonic_partner
             result_domain[power_space_index] = harmonic_domain
 
         # create random samples: one or two, depending on whether the