Smallest number such that concatenation is a square Challenge

Write a program or function that takes a number \$n\$ and returns the smallest \$k\$ such that concatenation \$n'k\$ is a square. This sequence is described by A071176 on the OEIS.

I/O Examples

input --&gt; output

1   --&gt;    6 (4^2)
10  --&gt;    0 (10^2)
35  --&gt;  344 (188^2)
164 --&gt;  836 (406^2)
284 --&gt; 2596 (1686^2)


Rules


Input will always be a positive decimal integer 
Output will be a positive decimal integer with no leading 0's or 0
Standard I/O rules apply
No standard loopholes
This is code-golf, so shortest code in bytes wins
05AB1E, 7 bytes
∞&lt;.Δ«Å²

Try it online or verify all test cases.
05AB1E (legacy), 8 bytes
[N«Å²#}N

Try it online or verify all test cases.
Alternative 8-byter which works in both 05AB1E versions (credit to @Grimmy):
[N«Å²iNq

Try it online (no test suite due to the program terminate q).
Explanation:

∞         # Push an infinite list in the range [1, ...]
 &lt;        # Decrease each by 1 to make the range [0, ...]
  .Δ      # Find the first value which is truthy for:
    «     #  Concat the value to the (implicit) input-integer
     Å²   #  And check whether it is a square number
          # (after which this found first value is output implicitly as result)

[         # Start an infinite loop:
 N«       #  Concat the 0-based loop index to the (implicit) input-integer
   Å²     #  If it's a square number:
     #    #   Stop the infinite loop
}N        # After the infinite loop has stopped: push the last index
          # (after which this found index is output implicitly as result)

[         # Start an infinite loop:
 N«       #  Concat the 0-based loop index to the (implicit) input-integer
   Å²i    #  If it's a square number:
      N   #   Push the index again
       q  #   And terminate the program
          #   (after which this index is output implicitly as result)

The legacy version didn't had the ∞ builtin, and in the new version it isn't possible to push the last index N after a loop is terminated, which is why I decided to post both solutions.